{"trustable":false,"prependHtml":"\u003cstyle type\u003d\u0027text/css\u0027\u003e\n .input, .output {\n border: 1px solid #888888;\n }\n .output {\n margin-bottom: 1em;\n position: relative;\n top: -1px;\n }\n .output pre, .input pre {\n background-color: #EFEFEF;\n line-height: 1.25em;\n margin: 0;\n padding: 0.25em;\n }\n \u003c/style\u003e\n \u003clink rel\u003d\"stylesheet\" href\u003d\"//codeforces.org/s/96598/css/problem-statement.css\" type\u003d\"text/css\" /\u003e\n\u003cscript\u003e\n window.katexOptions \u003d {\n delimiters: [\n {left: \u0027$$$$$$\u0027, right: \u0027$$$$$$\u0027, display: true},\n {left: \u0027$$$\u0027, right: \u0027$$$\u0027, display: false},\n {left: \u0027$$\u0027, right: \u0027$$\u0027, display: true},\n {left: \u0027$\u0027, right: \u0027$\u0027, display: false}\n ]\n };\n\u003c/script\u003e\n","sections":[{"title":"","value":{"format":"MD","content":"\u003cp\u003eDreamoon loves summing up something for no reason. One day he obtains two integers \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ea\u003c/i\u003e\u003c/span\u003e and \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003eb\u003c/i\u003e\u003c/span\u003e occasionally. He wants to calculate the sum of all \u003cspan class\u003d\"tex-font-style-it\"\u003enice\u003c/span\u003e integers. Positive integer \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ex\u003c/i\u003e\u003c/span\u003e is called \u003cspan class\u003d\"tex-font-style-it\"\u003enice\u003c/span\u003e if \u003cimg align\u003d\"middle\" class\u003d\"tex-formula\" src\u003d\"CDN_BASE_URL/003d5c3fc9ef0d0a3c94aa911906a5d0?v\u003d1682707237\" style\u003d\"max-width: 100.0%;max-height: 100.0%;\"\u003e and \u003cimg align\u003d\"middle\" class\u003d\"tex-formula\" src\u003d\"CDN_BASE_URL/8207e6295a0d96005d5c8170496e4d7d?v\u003d1682707237\" style\u003d\"max-width: 100.0%;max-height: 100.0%;\"\u003e, where \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ek\u003c/i\u003e\u003c/span\u003e is some \u003cspan class\u003d\"tex-font-style-bf\"\u003einteger\u003c/span\u003e number in range \u003cspan class\u003d\"tex-span\"\u003e[1, \u003ci\u003ea\u003c/i\u003e]\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003eBy \u003cimg align\u003d\"middle\" class\u003d\"tex-formula\" src\u003d\"CDN_BASE_URL/445e117d13a0d674f5c2c625be3917aa?v\u003d1682707237\" style\u003d\"max-width: 100.0%;max-height: 100.0%;\"\u003e we denote the \u003cspan class\u003d\"tex-font-style-it\"\u003equotient\u003c/span\u003e of integer division of \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ex\u003c/i\u003e\u003c/span\u003e and \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ey\u003c/i\u003e\u003c/span\u003e. By \u003cimg align\u003d\"middle\" class\u003d\"tex-formula\" src\u003d\"CDN_BASE_URL/6250fa19186cf37e43d1cfc18b68b797?v\u003d1682707237\" style\u003d\"max-width: 100.0%;max-height: 100.0%;\"\u003e we denote the \u003cspan class\u003d\"tex-font-style-it\"\u003eremainder\u003c/span\u003e of integer division of \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ex\u003c/i\u003e\u003c/span\u003e and \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ey\u003c/i\u003e\u003c/span\u003e. You can read more about these operations here: \u003cspan class\u003d\"tex-font-style-tt\"\u003ehttp://goo.gl/AcsXhT\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003eThe answer may be large, so please print its remainder modulo \u003cspan class\u003d\"tex-span\"\u003e1 000 000 007\u003c/span\u003e (\u003cspan class\u003d\"tex-span\"\u003e10\u003csup class\u003d\"upper-index\"\u003e9\u003c/sup\u003e + 7\u003c/span\u003e). Can you compute it faster than Dreamoon?\u003c/p\u003e\n\n定义 $div(x,b)$ 为整数除法,即 $div(5,2)\u003d2$,定义 $mod(x,b)$ 为求余,即 $mod(5,2)\u003d1$,求所有满足 $\\dfrac{div(x,b)}{mod(x,b)}\u003dk$ 的数 $x$ 的和,要求 $1\\leq k\\leq a$,给定 $a,b$。结果取对 $1e9+7$ 的余数输出。"}},{"title":"Input","value":{"format":"MD","content":"\u003cp\u003eThe single line of the input contains two integers \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ea\u003c/i\u003e\u003c/span\u003e, \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003eb\u003c/i\u003e\u003c/span\u003e (\u003cspan class\u003d\"tex-span\"\u003e1 ≤ \u003ci\u003ea\u003c/i\u003e, \u003ci\u003eb\u003c/i\u003e ≤ 10\u003csup class\u003d\"upper-index\"\u003e7\u003c/sup\u003e\u003c/span\u003e).\u003c/p\u003e"}},{"title":"Output","value":{"format":"MD","content":"\u003cp\u003ePrint a single integer representing the answer modulo \u003cspan class\u003d\"tex-span\"\u003e1 000 000 007\u003c/span\u003e (\u003cspan class\u003d\"tex-span\"\u003e10\u003csup class\u003d\"upper-index\"\u003e9\u003c/sup\u003e + 7\u003c/span\u003e).\u003c/p\u003e"}},{"title":"Sample 1","value":{"format":"MD","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003e1 1\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e0\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"Sample 2","value":{"format":"MD","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003e2 2\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e8\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"Note","value":{"format":"MD","content":"\u003cp\u003eFor the first sample, there are no nice integers because \u003cimg align\u003d\"middle\" class\u003d\"tex-formula\" src\u003d\"CDN_BASE_URL/030f190db1b5eb95a858cd3aa5465c0b?v\u003d1682707237\" style\u003d\"max-width: 100.0%;max-height: 100.0%;\"\u003e is always zero.\u003c/p\u003e\n\u003cp\u003eFor the second sample, the set of nice integers is \u003cspan class\u003d\"tex-span\"\u003e{3, 5}\u003c/span\u003e.\u003c/p\u003e"}}]}