n,m=map(int, input().split())
ans = 2*n-1
idx={}
val =[[] for j in range(m*(2*n+2))]
cnt = [0]*(m*(2*n+2))

for i in range(m):
    b = i*(2*n+2);
    for y in range(n):
        row = input().split()
        for x in range(n):
            c = int(row[x])
            if not c in idx:
                idx[c]=[]
            idx[c].append(b + y)
            val[b + y].append(c)
            idx[c].append(b + n + x)
            val[b + n + x].append(c)
            if y==x:
                idx[c].append(b+2*n)
                val[b+2*n].append(c)
            if n-1-y==x:
                idx[c].append(b+2*n+1)
                val[b+2*n+1].append(c)
for i in range(m):
    for j in range(2*n+2):
        for v in val[i*(2*n+2) + j]:
            for k in idx[v]:
                if not (i*(2*n+2) <= k and k < (i+1)*(2*n+2)):
                    cnt[k] += 1
                    ans = min(ans, 2*n-cnt[k]-1)
        for v in val[i*(2*n+2) + j]:
            for k in idx[v]:
                if not (i*(2*n+2) <= k and k < (i+1)*(2*n+2)):
                    cnt[k] -= 1
print(ans)