import sys
input = sys.stdin.readline

N,M=map(int,input().split())
CARD=[tuple(map(int,input().split())) for i in range(N*M)]

D=dict()
for i in range(N*M):
    D[CARD[i]]=i

def calc(L):

    #print("!",L)
    ANS=0
    count=5
    while count>0:
        #print(L)

        if L[0]>=count:
            x=L[0]//count
            ANS+=x
            for i in range(len(L)):
                L[i]-=x*count

        c=0

        while L:
            if L[0]<count:
                L.pop(0)
                c+=1
                continue

            for j in range(len(L)):
                L[j]-=count
            break
        if L==[]:
            break
        ANS+=1
        count-=c

    #print(ANS)
    return ANS
        
                
        

ANS=1<<63
for i in range(1,M+1):
    for j in range(5,N+1):
        LIST=[]

        for k in range(j-4,j+1):
            LIST.append(D[(k,i)])

        #print(sorted(LIST))

        ANS=min(ANS,calc(sorted(LIST)))

    LIST=[]
    for k in range(N-3,N+1):
        LIST.append(D[(k,i)])
    LIST.append(D[(1,i)])

    #print(sorted(LIST))

    ANS=min(ANS,calc(sorted(LIST)))

print(ANS)