#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define pii pair<int,int>
#define X first
#define Y second
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
void abc() {cout << endl;}
template <typename T, typename ...U> void abc(T i, U ...j) {
cout << i << ' ', abc(j...);
}
template <typename T> void printv(T l, T r) {
for (; l != r; ++l) cout << *l << " \n"[l + 1 == r];
}
#ifdef Doludu
#define test(x...) abc("[" + string(#x) + "]", x)
#define owo freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout)
#else
#define test(x...) void(0)
#define owo ios::sync_with_stdio(false), cin.tie(0)
#endif
const int N = 100000;
struct edge {
int v, c, p;
};
vector <edge> adj[N];
map <int, int> col_num[N];
int main () {
owo;
int n, m;
cin >> n >> m;
for (int i = 0, u, v, c, p; i < m; ++i) {
cin >> u >> v >> c >> p, --u, --v, --c;
adj[u].pb({v, c, p});
adj[v].pb({u, c, p});
col_num[u][c]++, col_num[v][c]++;
}
map <pair <pii, int>, int> dis;
dis[mp(mp(0, 0), -1)] = 0;
priority_queue <pair <int, pair <pii, int>>> pq;
pq.emplace(0, mp(mp(0, -1), 0));
while (!pq.empty()) {
int d, v, c, del; d = pq.top().X, tie(v, c) = pq.top().Y.X, del = pq.top().Y.Y; pq.pop();
if (d > dis[mp(mp(v, c), del)])
continue;
if (del)
col_num[v][c]--;
for (edge &e : adj[v]) {
if (col_num[v][e.c] == 1) {
// no change
if (!dis.count(mp(mp(e.v, e.c), 0)) || dis[mp(mp(e.v, e.c), 0)] > d) {
dis[mp(mp(e.v, e.c), 0)] = d;
pq.emplace(d, mp(mp(e.v, e.c), 0));
}
}
// change
if (!dis.count(mp(mp(e.v, e.c), 1)) || dis[mp(mp(e.v, e.c), 1)] > d + 1) {
dis[mp(mp(e.v, e.c), 1)] = d + 1;
pq.emplace(d + 1, mp(mp(e.v, e.c), 1));
}
}
if (del)
col_num[v][c]++;
}
int ans = 1 << 30;
for (auto A : dis) if (A.X.X.X == n - 1) {
ans = min(ans, A.Y);
}
if (ans == 1 << 30)
ans = -1;
cout << ans << endl;
}
