#include<bits/stdc++.h>
#include<atcoder/all>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;

int main(){
	int N, M, C;
	cin >> N >> M >> C;
	assert(N >= 1 && N <= 10);
	assert(M >= 1 && M <= N * (N - 1) / 2);
	assert(C >= 1 && C <= 100000);
	set<pair<int, int>> se;
	rep(i, M){
		int u, v, r, w;
		cin >> u >> v >> r >> w;
		if(cin.fail()) assert(false);
		assert(1 <= u && u < v && v <= N);
		if(se.find(make_pair(u, v)) != se.end()) assert(false);
		se.insert(make_pair(u, v));
	}
	return 0;
}