import math
def kyori(arr1,arr2) :
    x1,y1 = map(int,arr1)
    x2,y2 = map(int,arr2)
    if x1 == x2 :
        return abs(y1-y2)
    if y1 == y2 :
        return abs(x1-x2)
    return math.sqrt((x1-x2)**2 + (y1-y2)**2)

h,w = map(int,input().split(' '))
tgt = []
for i in range(h) :
    s = input()
    for j in range(w) :
        if s[j] == '1' :
            tgt.append((j+1,i+1))
#print(tgt)

sums = []
for i in range(h) : #左の列と右の列
    sum1 = sum2 = 0
    for j in range(len(tgt)) :
        k1 = kyori((0,i+1),tgt[j])
        sum1 += k1
        k2 = kyori((w+1,i+1),tgt[j])
        sum2 += k2
    sums.append(sum1)
    sums.append(sum2)

for i in range(w) : #上の行と下の行
    sum1 = sum2 = 0
    for j in range(len(tgt)) :
        k1 = kyori((i+1,0),tgt[j])
        #print(k1)
        sum1 += k1
        k2 = kyori((i+1,h+1),tgt[j])
        sum2 += k2
    sums.append(sum1)
    sums.append(sum2)
print(round(min(sums),8))