#include <bits/stdc++.h>   using namespace std;   char a[51][51];   int main() {     memset(a,  0 , sizeof(a));     int n;     cin >> n;     for (int i = 1; i <= n; i++)       for (int j = 1; j <= n; j++) cin >> a[i][j];     for (int i = 1; i <= n; i++)       for (int j = 1; j <= n; j++) {         int x = a[i][j] -  0 ;         if (x != 0) {           if (a[i - 1][j - 1] !=  0 ) x--;           if (a[i - 1][j + 1] !=  0 ) x--;           if (a[i + 1][j - 1] !=  0 ) x--;           if (a[i + 1][j + 1] !=  0 ) x--;           if (x != 0) return cout <<  No , 0;         }       }     cout <<  Yes ;     return 0;   }   