#!/usr/bin/ python3.8
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
import itertools

N, M = map(int, readline().split())
C = tuple(map(int, read().split()))


def get_bingos(n):
    n *= N * N
    for i in range(N):
        yield frozenset(C[n + N * i + j] for j in range(N))
        yield frozenset(C[n + N * j + i] for j in range(N))
    yield frozenset(C[n + N * j + j] for j in range(N))
    yield frozenset(C[n + N * (N - 1 - j) + j] for j in range(N))


bingos = tuple(tuple(get_bingos(i)) for i in range(M))


def solve_two_card(i, j):
    best = 0
    for S1, S2 in itertools.product(bingos[i], bingos[j]):
        common = len(S1 & S2)
        if best < common:
            best = common
    return N + N - best - 1


answer = min(solve_two_card(i, j) for i, j in itertools.combinations(range(M), 2))
print(answer)