#include<cstdio>#include<cstring>#include<iostream>#include<vector>#include<cmath>#include<algorithm>#include<cmath>#include<cstdlib>using namespace std;const int N = 10000+10;int f[N];void getFail(char *s,int f[]) { int m = strlen(s); f[0] = -1; for (int i = 1; i < m; i++) { int j = f[i-1]; while (j != -1 && s[j+1] != s[i]) j = f[j]; if (s[j+1] == s[i]) j++; f[i] = j; }}int n,m;char mz[N][80];int cnt[N];int check(char *s,int x) { int j = 0; for (int i = 0; i < m; i++) { if (s[i] != s[j]) return 0; j++; if (j > x) j = 0; } return 1;}void solve(int r){ f[0] = -1; for (int i = 1; i < n; i++) { int j = f[i-1]; while (j != -1 && strcmp(mz[j+1],mz[i])) j = f[j]; if (strcmp(mz[j+1],mz[i]) == 0) j++; f[i] = j; } printf("%dn",(n - 1 - f[n-1]) * (r));}int main(){ while (~scanf("%d%d",&n,&m)) { memset(cnt,0,sizeof(cnt)); for (int i = 0; i < n; i++) { scanf("%s",mz[i]); getFail(mz[i],f); int j = m-1; while (j != -1) { // cout<<m - 1 - f[j]<<endl; cnt[m - 1 - f[j]]++; j = f[j]; } } int r = 0; for (int i = 1; i <= m; i++) if (cnt[i] == n) { r = i; break; } for (int i = 0; i < n; i++) { mz[i][r] = 0; } solve(r); } return 0;}
