{"trustable":true,"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":"\u003cp\u003eVanya có \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003en\u003c/i\u003e\u003c/span\u003e khối lập phương. Anh ấy quyết định xây một kim tự tháp từ chúng. Vanya muốn xây kim tự tháp như sau: tầng đỉnh của kim tự tháp phải bao gồm \u003cspan class\u003d\"tex-span\"\u003e1\u003c/span\u003e khối, tầng thứ hai phải bao gồm \u003cspan class\u003d\"tex-span\"\u003e1 + 2 \u003d 3\u003c/span\u003e khối, tầng thứ ba phải có \u003cspan class\u003d\"tex-span\"\u003e1 + 2 + 3 \u003d 6\u003c/span\u003e khối, và cứ thế. Do đó, tầng thứ \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ei\u003c/i\u003e\u003c/span\u003e của kim tự tháp phải có \u003cspan class\u003d\"tex-span\"\u003e1 + 2 + ... + (\u003ci\u003ei\u003c/i\u003e - 1) + \u003ci\u003ei\u003c/i\u003e\u003c/span\u003e khối.\u003c/p\u003e\u003cp\u003eVanya muốn biết chiều cao tối đa của kim tự tháp mà anh ấy có thể xây dựng bằng số khối đã cho.\u003c/p\u003e"}},{"title":"Nhập","value":{"format":"HTML","content":"\u003cp\u003eDòng đầu tiên chứa số nguyên \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003en\u003c/i\u003e\u003c/span\u003e (\u003cspan class\u003d\"tex-span\"\u003e1 ≤ \u003ci\u003en\u003c/i\u003e ≤ 10\u003csup class\u003d\"upper-index\"\u003e4\u003c/sup\u003e\u003c/span\u003e) — số khối đã cho cho Vanya.\u003c/p\u003e"}},{"title":"Đầu ra","value":{"format":"HTML","content":"\u003cp\u003eIn ra chiều cao tối đa có thể của kim tự tháp trên một dòng duy nhất.\u003c/p\u003e"}},{"title":"Ví dụ 1","value":{"format":"HTML","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\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e1\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e"}},{"title":"Ví dụ 2","value":{"format":"HTML","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\u003e25\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e4\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e"}},{"title":"Ghi chú","value":{"format":"HTML","content":"\u003cp\u003eMinh họa cho ví dụ thứ hai: \u003c/p\u003e\u003ccenter\u003e \u003cimg class\u003d\"tex-graphics\" src\u003d\"CDN_BASE_URL/479aa16f527b4ff0ff6ae049fcbba73f?v\u003d1702908802\" style\u003d\"max-width: 100.0%;max-height: 100.0%;\"\u003e \u003c/center\u003e"}}]}