#include <iostream>
#include <vector>
#include <queue>
using namespace std;
typedef pair<int, int> P;
const int INF = 1 << 24;
int c[200][200];
int t[200][200];
int cost[200][200];
int tim[200][200];

int main(){
  int n, m, K;
  int p, q, r;
  while(cin >> n >> m && (n || m)){
    fill(&cost[0][0], &cost[199][199] + 1, INF);
    fill(&tim[0][0], &tim[199][199] + 1, INF);
    for(int i = 1; i <= m; i++){
      cost[i][i] = tim[i][i] = 0;
      c[i][i] = t[i][i] = 0;
    }

    for(int i = 0; i < n; i++){
      int a, b;
      int d, e;
      cin >> a >> b;
      cin >> d >> e;
      cost[b][a] = min(cost[b][a], d);
      cost[a][b] = min(cost[a][b], d);