from math import sqrt

def sum_dist(H: int, W: int, st: tuple) -> int:
    global P
    dist = 0
    for w in range(1,W+1):
        for h in range(1,H+1):
            if P[h-1][w-1] == 1:
                dist += sqrt((st[0]-w)**2 + (st[1]-h)**2)
     
    return dist           

H,W = map(int, input().split())
P = []
for i in range(H):
    P.append([int(p) for p in list(input().rstrip())])
    

INF = float("inf")
ans = INF

for w in range(1,W+1):
    ans_temp = sum_dist(H,W,(w,0))
    ans = min(ans, ans_temp)
    ans_temp = sum_dist(H,W,(w,H+1))
    ans = min(ans, ans_temp)
    
for h in range(1,H+1):
    ans_temp = sum_dist(H,W,(0,h))
    ans = min(ans, ans_temp)
    ans_temp = sum_dist(H,W,(W+1,h))
    ans = min(ans, ans_temp)
    
print(ans)