H,W = map(int, input().split())
lsp = [['0']*(W+2)]+[['0']+list(input())+['0'] for i in range(H)]+[['0']*(W+2)]
ans = float('INF')
def func(x,y):
    v = 0
    for i in range(1,H+1):
        for j in range(1,W+1):
            if lsp[i][j] == '1':
                v += ((x-i)**2+(y-j)**2)**(1/2)
    return v
for i in range(1,W+1):
    ans = min(ans,func(0, i))
    ans = min(ans,func(H+1, i))
for i in range(1,H+1):
    ans = min(ans,func(i, 0))
    ans = min(ans,func(i, W+1))
print(ans)