{"raw_statement":[{"iden":"problem statement","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?"},{"iden":"constraints","content":"*   $1 \\leq N \\leq 100$\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."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$\n$A$\n$B$\n$C$"},{"iden":"sample input 1","content":"4\nwest\neast\nwait"},{"iden":"sample output 1","content":"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`."},{"iden":"sample input 2","content":"9\ndifferent\ndifferent\ndifferent"},{"iden":"sample output 2","content":"0\n\nIf $A, B$ and $C$ are already equal in the beginning, the number of operations required is $0$."},{"iden":"sample input 3","content":"7\nzenkoku\ntouitsu\nprogram"},{"iden":"sample output 3","content":"13"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}