//記得跳題
#include<iostream>
#include<array>
#include<vector>
#include<string>
#include<algorithm>
#include<set>
#include<queue>
#include<stack>
#include<math.h>
#include<map>
#include<unordered_map>
#include<cstring>
#include<iomanip>
#include<bitset>
#include<tuple>
#define ll long long
#define LL __int128_t
#define DB double
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define REP(i,a,b) for(int i=a;i>=b;i--)
#define pb push_back
#define mp make_pair
#define INF (ll)(2e9)
#define MOD (ll)(1e9+7)
#define F first
#define S second
#define endl "\n"
#define AC ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
template<class T> using PQ=priority_queue<T,vector<T>,less<T> >;
void file(){
freopen("/Users/liaoyunyang/Desktop/meta_in.txt","r",stdin);
freopen("/Users/liaoyunyang/Desktop/meta_out.txt","w",stdout);
}
int s[200005],seg[800005];
void build(int id,int l,int r){
if(l==r){
seg[id]=s[l]; return;
}
int mid=(l+r)>>1;
build(id*2,l,mid);
build(id*2+1,mid+1,r);
seg[id]=max(seg[id*2],seg[id*2+1]);
}
int ask(int id,int l,int r,int L,int R){
if(l>R||r<L) return 0;
if(L<=l&&r<=R) return seg[id];
int mid=(l+r)>>1;
return max(ask(id*2,l,mid,L,R),ask(id*2+1,mid+1,r,L,R));
}
vector<pair<int,int> > e[205];
int c[50005],d[50005],a[50005],b[50005];
bool vis[2][205];
signed main(){
AC;
int n,m; cin>>n>>m;
FOR(i,0,m){
cin>>a[i]>>b[i]>>c[i]>>d[i];
e[a[i]].pb({b[i],i});
e[b[i]].pb({a[i],i+m});
}
int ans=INF;
queue<int> Q;
Q.push(1); vis[0][1]=1;
while(Q.size()){
int now=Q.front(); Q.pop();
for(auto k:e[now])if(!vis[0][k.F]&&k.S<m){
vis[0][k.F]=1; Q.push(k.F);
}
}
Q.push(n); vis[1][n]=1;
while(Q.size()){
int now=Q.front(); Q.pop();
for(auto k:e[now])if(!vis[1][k.F]&&k.S<m){
vis[1][k.F]=1; Q.push(k.F);
}
}
if(vis[0][n]&&vis[1][1]){
cout<<0<<endl; return 0;
}
FOR(i,0,m){
FOR(j,1,n+1) vis[0][j]=vis[1][j]=0;
queue<int> Q;
Q.push(1); vis[0][1]=1;
while(Q.size()){
int now=Q.front(); Q.pop();
for(auto k:e[now])if(!vis[0][k.F]&&k.S!=i&&(k.S<m||k.S==i+m)){
vis[0][k.F]=1; Q.push(k.F);
}
}
Q.push(n); vis[1][n]=1;
while(Q.size()){
int now=Q.front(); Q.pop();
for(auto k:e[now])if(!vis[1][k.F]&&k.S!=i&&(k.S<m||k.S==i+m)){
vis[1][k.F]=1; Q.push(k.F);
}
}
if(vis[0][n]&&vis[1][1]){
ans=min(ans,d[i]);
}
}
if(ans==INF) cout<<-1<<endl;
else cout<<ans<<endl;
}
/*
*/
