# -*- coding: utf-8 -*-
from math import sqrt

X = []
Y = []

H, W = map(int, input().split())

for h in range(1, H+1):
    for w, v in enumerate(map(int, input()), start=1):
        if v==0:
            continue
        X.append(w)
        Y.append(h)

rX = [0]*H + [W+1]*H + list(range(1, W+1)) + list(range(1, W+1))
rY = list(range(1, H+1)) + list(range(1, H+1)) + [0]*W + [H+1]*W

ans = 10**9

for rx, ry in zip(rX, rY):
    tmp = 0
    for x, y in zip(X, Y):
        tmp += sqrt((rx-x)**2 + (ry-y)**2)
    ans = min(tmp, ans)
print(ans)