from itertools import *
from bisect import *
from collections import *
from heapq import *
import sys

sys.setrecursionlimit(10 ** 6)

def II(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def SI(): return sys.stdin.readline()[:-1]
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
int1 = lambda x: int(x) - 1
def MI1(): return map(int1, sys.stdin.readline().split())
def LI1(): return list(map(int1, sys.stdin.readline().split()))
p2D = lambda x: print(*x, sep="\n")
dij = [(1, 0), (0, 1), (-1, 0), (0, -1)]

def main():
    n,m=MI()
    cards=[]
    for _ in range(m):
        cc=LLI(n)
        tmp=[]
        for row in cc:tmp.append(set(row))
        for col in zip(*cc):tmp.append(set(col))
        tmp.append(set(cc[i][i] for i in range(n)))
        tmp.append(set(cc[i][n-1-i] for i in range(n)))
        cards.append(tmp)
    #print(cards)
    mx=0
    for cj in range(m):
        c1=cards[cj]
        for ci in range(cj):
            c2=cards[ci]
            for bar1 in c1:
                for bar2 in c2:
                    mx=max(mx,len(bar1&bar2))
    print(2*n-1-mx)

main()