from math import *

def dist(x1, y1, x2, y2):
    return sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2)
    

H, W = map(int, input().split())
P = []
for i in range(H):
    L = list(input())
    L = list(map(int, L))
    P.append(L)
    
T = []
for i in range(W):
    T.append((-1, i))
    T.append((H, i))
for i in range(H):
    T.append((i, -1))
    T.append((i, W))
    
ans = 10 ** 18
for x, y in T:
    val = 0
    for i in range(H):
        for j in range(W):
            if P[i][j]:
                val += dist(x, y, i, j)
    ans = min(ans, val)
print(ans)