#include using namespace std; using i64 = long long; #define rep(i,s,e) for(int (i) = (s);(i) <= (e);(i)++) #define all(x) x.begin(),x.end() int H,W; vector> f; double calc(i64 x,i64 y){ double ans = 0; rep(i,1,H){ rep(j,1,W){ if(f[i][j]){ ans += sqrt((x - i) * (x - i) + (y - j) * (y - j)); } } } return ans; } int main(){ cin >> H >> W; f = vector>(H + 1,vector(W + 1)); rep(i,1,H){ string s; cin >> s; rep(j,1,W){ f[i][j] = s[j - 1] == '1'; } } double res = 1e18; rep(j,1,W){ res = min(res , calc(0,j)); res = min(res , calc(H + 1,j)); } rep(i,1,H){ res = min(res , calc(i,0)); res = min(res , calc(i,W + 1)); } cout << fixed << setprecision(8); cout << res << endl; }