#include <bits/stdc++.h>
using namespace std;
#define int long long
#define print(a) for(auto x : a) cout << x << ' '; cout << endl;
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, m;
cin >> n >> m;
vector<array<int, 3>> graph[n + 1];
map<int, int> p[n + 1];
for(int i = 0; i < m; i ++){
int a, b, c, P;
cin >> a >> b >> c >> P;
graph[a].push_back({b, c, P});
graph[b].push_back({a, c, P});
p[a][c] += P;
p[b][c] += P;
}
vector<int> mins(n + 1, 1e18);
set<array<int, 2>> s;
s.insert({0, 1});
mins[1] = 0;
while(!s.empty()){
array<int, 2> x = *s.begin();
s.erase(s.begin());
for(auto y : graph[x[1]]){
if(mins[y[0]] > x[0] + (p[x[1]][y[1]] > 1 ? 1 : 0)){
s.erase({mins[y[0]], y[0]});
mins[y[0]] = x[0] + (p[x[1]][y[1]] > 1 ? 1 : 0);
s.insert({mins[y[0]], y[0]});
}
}
}
if(mins[n] == 1e18)
cout << -1;
else
cout << mins[n];
}
