#include <bits/stdc++.h>
using namespace std;
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n,m; cin >> n >> m;
vector<tuple<int,int,int>> g[n+1];
for (int i = 0; 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});
}
bool odw[n+1]; fill(odw,odw+n+1,false);
long long odl[n+1], suma[m+1], opt[m+1], inf = 1000000000000000007; fill(odl,odl+n+1,inf);
priority_queue<pair<long long,int>,vector<pair<long long,int>>,greater<pair<long long,int>>> q;
odl[1] = 0, q.push({0,1});
while (!q.empty()) {
long long d = q.top().first;
int v = q.top().second; q.pop();
if (odw[v])
continue;
odw[v] = true;
for (auto [u,x,y] : g[v])
suma[x] = 0, opt[x] = inf;
for (auto [u,x,y] : g[v])
suma[x] += y;
for (auto [u,x,y] : g[v])
opt[x] = min(opt[x],suma[x]+odl[u]);
for (auto [u,x,y] : g[v]) {
long long w = min({odl[v]+y,odl[v]+suma[x]-y,opt[x]-y});
if (w < odl[u])
odl[u] = w, q.push({w,u});
}
}
cout << ((odl[n] == inf) ? -1 : odl[n]) << endl;
return 0;
}
