h, w = map(int, input().split())
P = [list(map(int, list(input()))) for _ in range(h)]

ans = 10**18
for cy in [-1, h]:
    for cx in range(w):
        res = 0
        for i in range(h):
            for j in range(w):
                if P[i][j] == 1:
                    res += ((i - cy)**2 + (j - cx)**2)**0.5
        ans = min(ans, res)

for cx in [-1, w]:
    for cy in range(h):
        res = 0
        for i in range(h):
            for j in range(w):
                if P[i][j] == 1:
                    res += ((i - cy)**2 + (j - cx)**2)**0.5
        ans = min(ans, res)
print(ans)