{"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":"HTML","content":"\u003cdiv\u003e \n \u003cp\u003e M爷最近特别爱吃香蕉,每天都要吃w根香蕉来保证自己的肠胃更健康~然而,他需要k元钱才能买到第一根香蕉,2k元钱才能买到第二根香蕉,以此类推(换句话说,买第i根香蕉需要花费他i*k元钱)\u003c/p\u003e \n \u003cp\u003e 他现在手上只有n元钱,请问他需要管他的土豪朋友jl姐姐借多少钱才能买得到w根香蕉\u003c/p\u003e \n \u003cp\u003e \u0026nbsp;\u003c/p\u003e \n\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\u003cdiv\u003e \n \u003cdiv\u003e \n \u003cp\u003e 三个数字\u003cspan\u003e\u003ci\u003ek\u003c/i\u003e, \u003ci\u003en\u003c/i\u003e, \u003ci\u003ew\u003c/i\u003e\u003c/span\u003e (\u003cspan\u003e1 ≤ \u003ci\u003ek\u003c/i\u003e, \u003ci\u003ew\u003c/i\u003e ≤ 1000\u003c/span\u003e, \u003cspan\u003e0 ≤ \u003ci\u003en\u003c/i\u003e ≤ 10\u003csup\u003e9\u003c/sup\u003e\u003c/span\u003e),分别表示第一根香蕉的价格,M爷手上所有的钱数以及他想吃的香蕉数\u003c/p\u003e \n \u003c/div\u003e \n\u003c/div\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cdiv\u003e \n \u003cdiv\u003e \n \u003cp\u003e 输出一个数,他需要再借的钱数,如果他不需要借钱,输出0。\u003c/p\u003e \n \u003c/div\u003e \n\u003c/div\u003e"}},{"title":"Sample Input","value":{"format":"HTML","content":"\u003cp\u003e 3 17 4 \u003c/p\u003e"}},{"title":"Sample Output","value":{"format":"HTML","content":"\u003cp\u003e 13\u003c/p\u003e"}}]}