import math
h,w = map(int,input().split())
lst = []
min_value = float('inf')

for i in range(h):
    n = list(input())
    for j in range(w):
        if n[j]=="1":
            lst.append([i+1,j+1])

def calc(h_index,w_index):
    value = 0
    for tgt in lst:
        value += math.sqrt((tgt[0]-h_index)**2 + (tgt[1]-w_index)**2)
    return value

for i in range(1,w+1):
    min_value = min(min_value,calc(0,i))
    min_value = min(min_value,calc(h+1,i))
for i in range(1,h+1):
    min_value = min(min_value,calc(i,0))
    min_value = min(min_value,calc(i,w+1))
print(min_value)