#include <bits/stdc++.h>
using namespace std;

int H, W;
int B[111][111];

double calc(int x, int y) {
   double ret = 0;
   for (int yi = 1; yi <= H; yi++) {
      for (int xi = 1; xi <= W; xi++) {
         if (B[yi][xi]) ret += hypot(y - yi, x - xi);
      }
   }
   return ret;
}

int main() {
   cin >> H >> W;
   for (int yi = 0; yi < H; yi++) {
      string s; cin >> s;
      for (int xi = 0; xi < W; xi++) {
         B[yi+1][xi+1] = s[xi] - '0';
      }
   }

   double ans = 1e8;
   for (int yi = 1; yi <= H; yi++) { ans = min(ans, calc(0, yi)); }
   for (int yi = 1; yi <= H; yi++) { ans = min(ans, calc(W+1, yi)); }
   for (int xi = 1; xi <= W; xi++) { ans = min(ans, calc(xi, 0)); }
   for (int xi = 1; xi <= W; xi++) { ans = min(ans, calc(xi, H+1)); }

   printf("%.10f\n", ans);

   return 0;
}