#include <bits/stdc++.h>
using namespace std;
const double INF = 10000000;
int main(){
  cout << fixed << setprecision(20);
  int H, W;
  cin >> H >> W;
  vector<vector<int>> P(H, vector<int>(W));
  for (int i = 0; i < H; i++){
    for (int j = 0; j < W; j++){
      char c;
      cin >> c;
      P[i][j] = c - '0';
    }
  }
  double ans = INF;
  for (int i = -1; i <= H; i++){
    for (int j = -1; j <= W; j++){
      if (!(0 <= i && i < H && 0 <= j && j < W)){
        double sum = 0;
        for (int y = 0; y < H; y++){
          for (int x = 0; x < W; x++){
            if (P[y][x] == 1){
              sum += sqrt(pow(y - i, 2) + pow(x - j, 2));
            }
          }
        }
        ans = min(ans, sum);
      }
    }
  }
  cout << ans << endl;
}