{"problem":{"name":"Touitsu","description":{"content":"You are given three strings $A, B$ and $C$. Each of these is a string of length $N$ consisting of lowercase English letters. Our objective is to make all these three strings equal. For that, you can r","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"nikkei2019_qual_b"},"statements":[{"statement_type":"Markdown","content":"You are given three strings $A, B$ and $C$. Each of these is a string of length $N$ consisting of lowercase English letters.\nOur objective is to make all these three strings equal. For that, you can repeatedly perform the following operation:\n\n*   Operation: Choose one of the strings $A, B$ and $C$, and specify an integer $i$ between $1$ and $N$ (inclusive). Change the $i$\\-th character from the beginning of the chosen string to some other lowercase English letter.\n\nWhat is the minimum number of operations required to achieve the objective?\n\n## Constraints\n\n*   $1 \\leq N \\leq 100$\n*   Each of the strings $A, B$ and $C$ is a string of length $N$.\n*   Each character in each of the strings $A, B$ and $C$ is a lowercase English letter.\n\n## Input\n\nInput is given from Standard Input in the following format:\n\n$N$\n$A$\n$B$\n$C$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"nikkei2019_qual_b","tags":[],"sample_group":[["4\nwest\neast\nwait","3\n\nIn this sample, initially $A =$ `west`、$B =$ `east`、$C =$ `wait`. We can achieve the objective in the minimum number of operations by performing three operations as follows:\n\n*   Change the second character in $A$ to `a`. $A$ is now `wast`.\n*   Change the first character in $B$ to `w`. $B$ is now `wast`.\n*   Change the third character in $C$ to `s`. $C$ is now `wast`."],["9\ndifferent\ndifferent\ndifferent","0\n\nIf $A, B$ and $C$ are already equal in the beginning, the number of operations required is $0$."],["7\nzenkoku\ntouitsu\nprogram","13"]],"created_at":"2026-03-03 11:01:14"}}