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

#define ll long long
#define vvi vector<vector<int>>
#define vec vector
#define pq priority_queue
#define all(v) (v).begin(), (v).end()
#define uniqueV(x) sort(x.begin(), x.end()); x.erase(unique(x.begin(), x.end()), x.end());
#define rep(i, n) for (int (i) = (0); (i) < (n); ++(i))
#define repp(i, m, n) for (int (i) = (m); (i) < (n); ++(i))
#define dbg(x) cerr << #x << ": " << x << endl;
#define dbg2(x, y) cerr<<"("<<#x<<", "<<#y<<") = "<<"("<<x<<", "<<y<<")"<<endl;
#define dbg3(x, y, z) cerr<<"("<<#x<<", "<<#y<<", "<<#z<<") = "<<"("<<x<<", "<<y<<", "<<z<<")"<<endl;
#define dbgB(value, size) cerr<<#value<<": "<<bitset<size>(value) << endl;
#define line() cerr << "---------------" << endl;

const int dx[] = {1, -1, 0, 0};
const int dy[] = {0, 0, -1, 1};
const double PI = 3.14159265358979323846;

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a = b; return 1; } return 0; }

template<typename T>
void printA(vector<T> &printArray, char between = ' ') {
   int paSize = printArray.size();
   for (int i = 0; i < paSize; i++) { cerr << printArray[i] << between;}
   if (between != '\n') {cerr << endl;}
}

// ------------------------------------------------------------------------------------------

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

void print() {
   for (int i = 0; i <= H+1; i++) {
      for (int j = 0; j <= W+1; j++) {
         cout << B[i][j];
      }
      cout << endl;
   }
}

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

int main() {
   cin >> H >> W;
   rep (i, H) {
      string s; cin >> s;
      rep (j, W) {
         B[i+1][j+1] = s[j] - '0';
      }
   }

   double ans = 1e8;
   for (int y = 1; y <= H; y++) { chmin(ans, calc(0, y)); }
   for (int y = 1; y <= H; y++) { chmin(ans, calc(W+1, y)); }
   for (int x = 1; x <= W; x++) { chmin(ans, calc(x, 0)); }
   for (int x = 1; x <= W; x++) { chmin(ans, calc(x, H+1)); }

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

   return 0;
}