H, W = map(int, input().split())
A = [[-1] * (W + 2) for _ in range(H + 2)]
for i in range(1, H + 1):
    A[i] = [-1] + list(map(int, input().rstrip())) + [-1]
A[0][0], A[0][W + 1], A[i + 1][0], A[i + 1][W + 1] = -2, -2, -2, -2
ans = 1e9
for i in range(0, H + 2):
    for j in range(0, W + 2):
        if A[i][j] == -1:
            sum = 0
            for x in range(1, H + 1):
                for y in range(1, W + 1):
                    if A[x][y] == 1:
                        d = ((i - x) * (i - x) + (j - y) * (j - y)) ** 0.5
                        sum += d
            ans = min(ans, sum)
print(ans)