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

int main()
{
	int64_t h, w;
	cin >> h >> w;
	string s[h];
	for (auto &i : s)
	{
		cin >> i;
	}
	double ans = (1ll << 60);
	for (int i = 0; i <= h + 1; i++)
	{
		for (int j = 0; j <= w + 1; j++)
		{
			if (i != 0 && i != h + 1 && j != 0 && j != w + 1)
			{
				continue;
			}
			double tmp = 0;
			for (int k = 1; k <= h; k++)
			{
				for (int l = 1; l <= w; l++)
				{
					if (s[k - 1][l - 1] == '1')
					{
						tmp += sqrt((i - k) * (i - k) + (j - l) * (j - l));
					}
				}
			}
			ans = min(ans, tmp);
		}
	}
	cout << fixed << setprecision(20) << ans << endl;
	return 0;
}