{"trustable":true,"prependHtml":"\u003cstyle type\u003d\"text/css\"\u003e\n div.illustration {\n float: right;\n padding-left: 20px;\n }\n div.illustration .illustration {\n width: 100%;\n border-radius: 4px;\n }\n pre {\n display: block;\n margin: 0 0 10px;\n font-size: 13px;\n line-height: 1.42857143;\n color: #333;\n word-break: break-all;\n word-wrap: break-word;\n }\n\u003c/style\u003e\n\u003cscript\u003e\n window.katexOptions \u003d {\n delimiters: [\n {left: \u0027\\\\[\u0027, right: \u0027\\\\]\u0027, display: true}\n ]\n };\n\u003c/script\u003e\n","sections":[{"title":"","value":{"format":"HTML","content":"\n \u003cp\u003eYou are teaching kindergarten! You wrote down the numbers\n from \u003cspan class\u003d\"tex2jax_process\"\u003e$1$\u003c/span\u003e to \u003cspan class\u003d\"tex2jax_process\"\u003e$n$\u003c/span\u003e, in order, on a whiteboard. When\n you weren’t paying attention, one of your students erased one\n of the numbers.\u003c/p\u003e\n \u003cp\u003eCan you tell which number your mischievous student\n erased?\u003c/p\u003e\n \u003ch2\u003eInput\u003c/h2\u003e\n \u003cp\u003eThe first line of input contains a single integer\n \u003cspan class\u003d\"tex2jax_process\"\u003e$n$\u003c/span\u003e (\u003cspan class\u003d\"tex2jax_process\"\u003e$2 \\le n \\le 100$\u003c/span\u003e), which is the\n number of numbers that you wrote down.\u003c/p\u003e\n \u003cp\u003eThe second line of input contains a string of digits, which\n represents the numbers you wrote down (minus the one that has\n been erased). There are no spaces in this string. It is\n guaranteed to contain all of the numbers from \u003cspan class\u003d\"tex2jax_process\"\u003e$1$\u003c/span\u003e to \u003cspan class\u003d\"tex2jax_process\"\u003e$n$\u003c/span\u003e, in order, except for the single\n number that the student erased.\u003c/p\u003e\n \u003ch2\u003eOutput\u003c/h2\u003e\n \u003cp\u003eOutput a single integer, which is the number that the tricky\n student erased.\u003c/p\u003e\n \u003ch2\u003eSample 1\u003c/h2\u003e\u003cbody\u003e\u003ctable class\u003d\"vjudge_sample\"\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\u003e5\n1235\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\n\u003c/body\u003e\n \u003ch2\u003eSample 2\u003c/h2\u003e\u003cbody\u003e\u003ctable class\u003d\"vjudge_sample\"\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\u003e10\n1234568910\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e7\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/body\u003e\n \u003ch2\u003eSample 3\u003c/h2\u003e\u003cbody\u003e\u003ctable class\u003d\"vjudge_sample\"\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\u003e15\n1234567891012131415\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e11\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/body\u003e\n "}}]}