h, w = map(int, input().split())
info = [["2"]*(h+2)] + [["2"] + list(input()) + ["2"] for i in range(h)] + [["2"]*(h+2)]

def solve(i,j):
    ans = 0
    for k in range(h+2):
        for l in range(w+2):
            if info[k][l] == "1":
                ans += ((i-k)**(2) + (j-l)**(2))**(0.5)
    return ans

min_ans = 100000000000000
for i in range(h+2):
    for j in range(w+2):
        if info[i][j] == "2":
            ans = solve(i, j)
            min_ans = min(ans, min_ans)
print(min_ans)