#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=l;i<r;i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=(r)-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[8]={1,0,-1,0,1,1,-1,-1};
const ll dx[8]={0,-1,0,1,1,-1,1,-1};
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

const int mod = MOD9;
const int max_n = 200005;
struct mint {
  ll x; // typedef long long ll;
  mint(ll x=0):x((x%mod+mod)%mod){}
  mint operator-() const { return mint(-x);}
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod-a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this;}
  mint operator+(const mint a) const { return mint(*this) += a;}
  mint operator-(const mint a) const { return mint(*this) -= a;}
  mint operator*(const mint a) const { return mint(*this) *= a;}
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t>>1);
    a *= a;
    if (t&1) a *= *this;
    return a;
  }
  bool operator==(const mint &p) const { return x == p.x; }
  bool operator!=(const mint &p) const { return x != p.x; }
  // for prime mod
  mint inv() const { return pow(mod-2);}
  mint& operator/=(const mint a) { return *this *= a.inv();}
  mint operator/(const mint a) const { return mint(*this) /= a;}
};
istream& operator>>(istream& is, mint& a) { return is >> a.x;}
ostream& operator<<(ostream& os, const mint& a) { return os << a.x;}

struct combination {
  vector<mint> fact, ifact;
  combination(int n):fact(n+1),ifact(n+1) {
    assert(n < mod);
    fact[0] = 1;
    for (int i = 1; i <= n; ++i) fact[i] = fact[i-1]*i;
    ifact[n] = fact[n].inv();
    for (int i = n; i >= 1; --i) ifact[i-1] = ifact[i]*i;
  }
  mint operator()(int n, int k) {
    if (k < 0 || k > n) return 0;
    return fact[n]*ifact[k]*ifact[n-k];
  }
  mint P(int n, int k){
    return fact[n]*ifact[n-k];
  }
}comb(max_n);

template <class T>
class SegTree {
    int n;// 葉の数
    vector<T> data;// データを格納するvector
    T def; // 初期値かつ単位元
    function<T(T, T)> operation; // 区間クエリで使う処理
    function<T(T, T)> update;// 点更新で使う処理

    T find(int a, int b) {
        T val_left = def, val_right = def;
        for (a += (n - 1), b += (n - 1); a < b; a >>= 1, b >>= 1)
        {
            if ((a & 1) == 0){
                val_left = operation(val_left, data[a]);
            }
            if ((b & 1) == 0){
                val_right = operation(data[--b],val_right);
            }
        }
        return operation(val_left, val_right);
    }
    public:
    // _n:必要サイズ, _def:初期値かつ単位元, _operation:クエリ関数,
    // _update:更新関数
    SegTree(size_t _n, T _def, function<T(T, T)> _operation,
        function<T(T, T)> _update=[](T a,T b){return b;})
        : def(_def), operation(_operation), update(_update) {
        n = 1;
        while (n < _n) {
            n *= 2;
        }
        data = vector<T>(2 * n - 1, def);
    }
    void set(int i, T x) { data[i + n - 1] = x; }
    void build() {
        for (int k=n-2;k>=0;k--) data[k] = operation(data[2*k+1],data[2*k+2]);
    }
    // 場所i(0-indexed)の値をxで更新
    void change(int i, T x) {
        i += n - 1;
        data[i] = update(data[i], x);
        while (i > 0) {
            i = (i - 1) / 2;
            data[i] = operation(data[i * 2 + 1], data[i * 2 + 2]);
        }
    }

    // [a, b)の区間クエリを実行
    T query(int a, int b) {
        //return _query(a, b, 0, 0, n);
        return find(a,b);
    }

    // 添字でアクセス
    T operator[](int i) {
        return data[i + n - 1];
    }
};

struct Edge{
    ll to,cost;
};
template<typename T>
struct Dijkstra{
    vector<T> dist;
    vector<int> prev;
    Dijkstra(vector<vector<Edge>> &g,int s){
        dist=vector<T>(g.size(),numeric_limits<T>::max()/5);
        prev=vector<int>(g.size(),-1);
        using pi=pair<T,int>;
        priority_queue<pi,vector<pi>,greater<pi>> que;
        dist[s]=0;
        que.emplace(dist[s],s);
        while(!que.empty()){
            T cost;int idx;
            tie(cost,idx)=que.top();que.pop();
            if(dist[idx]<cost)continue;
            for(auto &e:g[idx]){
                T ncost=cost+e.cost;
                if(dist[e.to]<=ncost)continue;
                prev[e.to]=idx;
                dist[e.to]=ncost;
                que.emplace(dist[e.to],e.to);
            }
        }
    }
    vector<int> get_path(int t){//到達できない場合、return=t;
        vector<int> path;
        for (int cur = t; cur != -1; cur = prev[cur]) {
            path.push_back(cur);
        }
        reverse(path.begin(), path.end());
        return path;
    }
};

int main(){
    ll n,m;cin >> n >> m;
    vpl cst(m);
    vpl pls(m);
    vector<vector<Edge>> d(n);
    rep(i,m){
        ll x,y;cin >> x >> y;x--;y--;
        cin >> cst[i].fi >> cst[i].se;
        d[x].pb({y,cst[i].fi});
        d[y].pb({x,cst[i].fi});
        pls[i]={x,y};
    }
    Dijkstra<ll> ds(d,0);
    vector<int> p=ds.get_path(n-1);
    ll ans=ds.dist[n-1];
    set<pl> st;
    rep(i,p.size()-1){
        ll x=p[i],y=p[i+1];
        st.ins({x,y});
    }
    vector<vector<Edge>> e(n);
    rep(i,m){
        if(st.count(pls[i])){
            e[pls[i].fi].pb({pls[i].se,cst[i].se});
            e[pls[i].se].pb({pls[i].fi,cst[i].se});
            continue;
        }
        swap(pls[i].fi,pls[i].se);
        if(st.count(pls[i])){
            e[pls[i].fi].pb({pls[i].se,cst[i].se});
            e[pls[i].se].pb({pls[i].fi,cst[i].se});
            continue;
        }
        e[pls[i].fi].pb({pls[i].se,cst[i].fi});
        e[pls[i].se].pb({pls[i].fi,cst[i].fi});
    }
    Dijkstra<ll> dss(e,n-1);
    cout << ans+dss.dist[0] <<endl;
}