# 立ち位置は初期から不変
# 立ち位置 (H + W) * 2
# 各立ち位置での作業時間計算 H*W
# 全体 O((H+W)HW)

H, W = map(int, input().split())
S = [input() for _ in range(H)]

black = set()
for i in range(H):
    for j in range(W):
        if S[i][j] == "1":
            black.add((j+1,i+1))

ans = float("inf")
for y0 in [0,H+1]:
    for x0 in range(1,W+1):
        tmp = 0
        for x, y in black:
            tmp += ((x-x0)**2 + (y-y0)**2) ** 0.5
        ans = min(ans, tmp)

for x0 in [0,W+1]:
    for y0 in range(1,H+1):
        tmp = 0
        for x, y in black:
            tmp += ((x-x0)**2 + (y-y0)**2) ** 0.5
        ans = min(ans, tmp)

print(ans)