from itertools import permutations N,M=map(int,input().split()) X=[0]*M for i in range(M): x,y,a=map(int,input().split()) X[i]=(x,y,a) Max=-1 Index=[0]*N for U in permutations(range(N)): T=0 for i in range(N): Index[U[i]]=i for (x,y,a) in X: if Index[x]Max: Max=T print(Max)