H,W=map(int,input().split())
list1=[]
list2=[]
for i in range(W+2):
    list2.append(0)
list1.append(list2)
list2=[]

for j in range(H):
    list3=[0]
    s=input()
    for k in range(W):
        list3.append(int(s[k]))
    list3.append(0)
    list1.append(list3)
    list3=[0]
i=0
for i in range(W+2):
    list2.append(0)
list1.append(list2)
list2=[]

#print(list1)

listA=[]
for a in range(H+2):
    
    for b in range(W+2):
        
        if a==0 or a==H+1:
            if b==0 or b==W+1:
                pass
            else:
                le=0
                for c in range(1,H+1):
                    for d in range(1,W+1):
                        if list1[c][d]==1:
                            le+=((a-c)**2+(b-d)**2)**0.5
                listA.append(le)
                le=0
        elif b==0 or b==W+1:
            le=0
            for c in range(1,H+1):
                for d in range(1,W+1):
                    if list1[c][d]==1:
                        le+=((a-c)**2+(b-d)**2)**0.5
            listA.append(le)
            le=0
print(min(listA))