#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
using namespace std;
using namespace __gnu_pbds;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
const int NMAX = 1e5;
const ll INF = 1e18;
struct PQElement {
int node, parent, parent_c;
ll d;
bool operator < (const PQElement &other) const {
return other.d < d;
}
};
struct Edge {
int next_node, c, p;
Edge(int next_node, int c, int p) : next_node(next_node), c(c), p(p) {}
};
int n, m;
ll d[NMAX + 1];
vector<Edge> g[NMAX + 1];
unordered_map<int, int> mp[NMAX + 1];
void Dijkstra(int start) {
for(int i = 1; i <= n; i++) {
d[i] = INF;
}
priority_queue<PQElement> pq;
pq.push({start, 0});
while(!pq.empty()) {
auto [node, parent, parent_c, curent_d] = pq.top();
pq.pop();
if(d[node] == INF) {
d[node] = curent_d;
for(auto [next_node, c, p] : g[node]) {
if(mp[node][c] - (parent_c == c) == 1) {
pq.push({next_node, node, 0, curent_d});
}
else {
pq.push({next_node, node, c, curent_d + p});
}
}
}
}
}
int main() {
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, p;
cin >> a >> b >> c >> p;
g[a].emplace_back(b, c, p);
mp[a][c]++;
g[b].emplace_back(a, c, p);
mp[b][c]++;
}
Dijkstra(1);
cout << (d[n] == INF ? -1 : d[n]);
return 0;
}
