#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
//using namespace __gnu_pbds;
#define LongDepTrai "robot"
#define ll long long
#define ull unsigned long long
#define ld long double
#define ii pair<int,int>
#define iii pair<int,ii>
#define iv pair<ii,ii>
#define pll pair<ll,ll>
#define vi vector<int>
#define vii vector<ii>
#define vll vector<ll>
#define fi first
#define se second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(x) int((x).size())
#define order_set(T) tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>
inline ll add(ll a, ll b, ll mod){ a += b; if(a >= mod) a -= mod; return a; }
inline ll sub(ll a, ll b, ll mod){ a -= b; if(a < 0) a += mod; return a; }
inline ll mul(ll a, ll b, ll mod){ return ( (ll)a * b ) % mod; }
static mt19937_64 rng((unsigned)chrono::steady_clock::now().time_since_epoch().count());
const int N=1e6+9;
const int INF=2e9;
int n,m,c[N],p[N],cnt=0,sum[N],f[N];
vii g[N];
map<int,int> mp[N];
int idx(int u,int c){
if(u>n) return u;
if(mp[u][c]==0) mp[u][c]=(++cnt);
return mp[u][c];
}
void dijk(int u){
for(int i=1;i<=cnt;i++){
f[i]=INF;
}
f[u]=0;
priority_queue<ii,vector<ii>,greater<ii>> q;
q.push({f[u],u});
while(q.size())
{
int z=q.top().se;
int val=q.top().fi;
q.pop();
if(val!=f[z]) continue;
for(ii x:g[z]){
int v=x.fi;
int id=x.se;
if(f[v]>f[z]+sum[idx(z,c[id])]-p[id]){
f[v]=f[z]+sum[idx(z,c[id])]-p[id];
q.push({f[v],v});
}
if(z>n) continue;
if(f[v]>f[z]+p[id]){
f[v]=f[z]+p[id];
q.push({f[v],v});
}
if(f[idx(v,c[id])]>val){
f[idx(v,c[id])]=val;
q.push({f[idx(v,c[id])],idx(v,c[id])});
}
}
}
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
if(fopen(LongDepTrai".inp","r")){
freopen(LongDepTrai".inp","r",stdin);
freopen(LongDepTrai".out","w",stdout);
}
cin>>n>>m;
cnt=n;
for(int i=1;i<=m;i++){
int u,v,col,cost;
cin>>u>>v>>col>>cost;
c[i]=col;
p[i]=cost;
g[u].pb({v,i});
g[v].pb({u,i});
// cout<<u<<" "<<v<<"\n";
// cout<<v<<" "<<u<<"\n";
sum[idx(v,col)]+=p[i];
g[idx(v,col)].pb({u,i});
// cout<<idx(v,col)<<" "<<u<<"\n";
sum[idx(u,col)]+=p[i];
g[idx(u,col)].pb({v,i});
// cout<<idx(u,col)<<" "<<v<<"\n";
}
dijk(1);
cout<<f[n];
return 0;
}
