#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int ll
typedef pair<int, int> pi;
typedef vector <int> vi;
typedef vector <pi> vpi;
typedef pair <pi,pi> pipi;
typedef pair<pi, ll> pii;
typedef set <ll> si;
typedef long double ld;
#define f first
#define s second
#define mp make_pair
#define FOR(i,s,e) for(int i=s;i<=int(e);++i)
#define DEC(i,s,e) for(int i=s;i>=int(e);--i)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define lbd(x, y) lower_bound(all(x), y)
#define ubd(x, y) upper_bound(all(x), y)
#define aFOR(i,x) for (auto i: x)
#define mem(x,i) memset(x,i,sizeof x)
#define fast ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define maxn 1000010
#define INF (ll)1e18
#define MOD 1000000007
typedef pair <vi, int> pvi;
typedef pair <int,pi> ipi;
typedef vector <pii> vpii;
#define DEBUG 0
int N,M;
int a,b,c,p;
int sm[maxn];
vector <ipi> adj[maxn];
vector <pi> adj2[maxn];
int dist[maxn];
int32_t main(){
cin >> N >> M;
FOR(i,1,M){
cin >> a >> b >> c >> p;
adj[a].pb(ipi(b, pi(c,p)));
adj[b].pb(ipi(a,pi(c,p)));
}
FOR(i,1,N){
aFOR(j, adj[i]) sm[j.s.f] += j.s.s;
aFOR(j, adj[i]){
adj2[i].pb(pi(j.f, min(j.s.s, sm[j.s.f] - j.s.s)));
}
aFOR(j, adj[i]) sm[j.s.f] = 0;
}
priority_queue <pi,vector <pi>, greater <pi> > pq;
pq.push(pi(0,1));
mem(dist,-1);
dist[1] = 0;
while (!pq.empty()){
pi x = pq.top(); pq.pop();
//cout << x.s << '\n';
if (x.f != dist[x.s]) continue;
aFOR(i, adj2[x.s]){
if (dist[i.f] == -1 || dist[i.f] > x.f + i.s){
dist[i.f] = x.f + i.s;
pq.push(pi(dist[i.f], i.f));
}
}
}
cout << dist[N];
}
