#include <bits/stdc++.h>
using namespace std;
int n, m;
double bilv = 0;
int ansa = 0, ansb = 1;
vector<pair<int, pair<int, int> > > g[1005];
bool vis[1005];
int d[1005];
void spfa(int s, int minf) {
  memset(d, 0x3f, sizeof(d));
  memset(vis, 0, sizeof(vis));
  deque<int> q;
  q.push_back(s);
  vis[s] = true;
  d[s] = 0;
  d[0] = 0;
  while (!q.empty()) {
    int x = q.front();
    q.pop_front();
    vis[x] = 0;
    for (int i = 0; i < g[x].size(); i++) {
      int y = g[x][i].first, w = g[x][i].second.first, f = g[x][i].second.second;
      if (d[y] > d[x] + w && f >= minf) {
        d[y] = d[x] + w;
        if (!vis[y]) {
          if(!q.empty() && d[y] <= d[q.front()]) q.push_front(y);
          else q.push_back(y);
          if(!q.empty() && d[q.front()] > d[q.back()]) swap(q[0], q[q.size() - 1]);
          vis[y] = 1;
        }
      }
    }
  }
}
int main() {
  freopen("pump.in", "r", stdin);
  freopen("pump.out", "w", stdout);
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  cin >> n >> m;
  for(int i = 1; i <= m; i++) {
    int a, b, c, d;
    cin >> a >> b >> c >> d;
    g[a].push_back({b, {c, d}});
    g[b].push_back({a, {c, d}});
  }
  for(int i = 1; i <= 1000; i++) {
    spfa(1, i);
    if(d[n] == 0x3f3f3f3f) break;
    else bilv = max(bilv, floor((i * 1.0 / d[n]) * 1000000));
  }
  cout << fixed << setprecision(0) << bilv << endl;
  return 0;
}