#include<bits/stdc++.h>
using namespace std;
#define ALL(x) begin(x),end(x)
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define mod 1000000007
using ll=long long;
const int INF=1000000000;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
// ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

struct IOSetup{
    IOSetup(){
        cin.tie(0);
        ios::sync_with_stdio(0);
        cout<<fixed<<setprecision(12);
    }
} iosetup;
 
template<typename T>
ostream &operator<<(ostream &os,const vector<T>&v){
    for(int i=0;i<(int)v.size();i++) os<<v[i]<<(i+1==(int)v.size()?"":" ");
    return os;
}
template<typename T>
istream &operator>>(istream &is,vector<T>&v){
    for(T &x:v)is>>x;
    return is;
}

#line 1 "Graph2/GraphTemplate.cpp"
// graph template
// ref : https://ei1333.github.io/library/graph/graph-template.cpp
template<typename T=int>
struct Edge{
    int from,to;
    T w;
    int idx;
    Edge()=default;
    Edge(int from,int to,T w=1,int idx=-1):from(from),to(to),w(w),idx(idx){}
    operator int() const{return to;}
};

template<typename T=int>
struct Graph{
    vector<vector<Edge<T>>> g;
    int V,E;
    Graph()=default;
    Graph(int n):g(n),V(n),E(0){}

    size_t size(){
        return g.size();
    }
    void resize(int k){
        g.resize(k);
    }
    inline const vector<Edge<T>> &operator[](int k)const{
        return (g.at(k));
    }
    inline vector<Edge<T>> &operator[](int k){
        return (g.at(k));
    }
    void add_directed_edge(int from,int to,T cost=1){
        g[from].emplace_back(from,to,cost,E++);
    }
    void add_edge(int from,int to,T cost=1){
        g[from].emplace_back(from,to,cost,E);
        g[to].emplace_back(to,from,cost,E++);
    }
    void read(int m,int pad=-1,bool weighted=false,bool directed=false){
        for(int i=0;i<m;i++){
            int u,v;cin>>u>>v;
            u+=pad,v+=pad;
            T w=T(1);
            if(weighted) cin>>w;
            if(directed) add_directed_edge(u,v,w);
            else         add_edge(u,v,w);
        }
    }
};
#line 2 "Graph2/StronglyConnectedComponents.cpp"

// scc.belong[i]    : strongly connected components i belongs 
// scc.group[i]   : vertice i-th strongly connected component has
// scc.compressed : compressed Graph, DAG
template<typename T=int>
struct StronglyConnectedComponents{
    private:
    Graph<T> g,rg;
    vector<int> check;
    void dfs(int cur,vector<int> &ord){
        for(auto &to:g[cur])if(!check[to]){
            check[to]=true;
            dfs(to,ord);
        }
        ord.push_back(cur);
    }
    void rdfs(int cur,int p){
        for(auto &to:rg[cur])if(belong[to]==-1){
            belong[to]=p;
            rdfs(to,p);
        }
    }

    public:
    vector<int> belong;
    vector<vector<int>> group;
    Graph<T> compressed;
    
    StronglyConnectedComponents(Graph<T> &g):g(g),rg(g.size()),check(g.size()),belong(g.size(),-1){
        for(int i=0;i<(int)g.size();i++)for(auto &e:g[i]) rg.add_directed_edge(e.to,e.from,e.w);
        build();
    }
    // return compressed graph
    void build(){
        vector<int> ord;
        for(int i=0;i<(int)g.size();i++)if(!check[i]){
            check[i]=true;
            dfs(i,ord);
        }
        int ptr=0;;
        for(int i=(int)ord.size()-1;i>=0;i--)if(belong[ord[i]]==-1){
            belong[ord[i]]=ptr;
            rdfs(ord[i],ptr);ptr++;
        }
        compressed.resize(ptr);
        group.resize(ptr);
        for(int i=0;i<(int)g.size();i++){
            int u=belong[i];
            group[u].push_back(i);
            for(auto &e:g[i]){
                int v=belong[e];
                if(u!=v) compressed.add_directed_edge(u,v,e.w);
            }
        }
        return ;
    }
};


template<ll Mod>
struct ModInt{
    long long x;
    ModInt():x(0){}
    ModInt(long long y):x(y>=0?y%Mod:(Mod-(-y)%Mod)%Mod){}
    ModInt &operator+=(const ModInt &p){
        if((x+=p.x)>=Mod) x-=Mod;
        return *this;
    }
    ModInt &operator-=(const ModInt &p){
        if((x+=Mod-p.x)>=Mod)x-=Mod;
        return *this;
    }
    ModInt &operator*=(const ModInt &p){
        x=(int)(1ll*x*p.x%Mod);
        return *this;
    }
    ModInt &operator/=(const ModInt &p){
        (*this)*=p.inverse();
        return *this;
    }
    ModInt operator-()const{return ModInt(-x);}
    ModInt operator+(const ModInt &p)const{return ModInt(*this)+=p;}
    ModInt operator-(const ModInt &p)const{return ModInt(*this)-=p;}
    ModInt operator*(const ModInt &p)const{return ModInt(*this)*=p;}
    ModInt operator/(const ModInt &p)const{return ModInt(*this)/=p;}
    bool operator==(const ModInt &p)const{return x==p.x;}
    bool operator!=(const ModInt &p)const{return x!=p.x;}
    ModInt inverse()const{
        int a=x,b=Mod,u=1,v=0,t;
        while(b>0){
            t=a/b;
            swap(a-=t*b,b);swap(u-=t*v,v);
        }
        return ModInt(u);
    }
    ModInt pow(long long n)const{
        ModInt ret(1),mul(x);
        while(n>0){
            if(n&1) ret*=mul;
            mul*=mul;n>>=1;
        }
        return ret;
    }
    friend ostream &operator<<(ostream &os,const ModInt &p){return os<<p.x;}
    friend istream &operator>>(istream &is,ModInt &a){long long t;is>>t;a=ModInt<Mod>(t);return (is);}
    static int get_mod(){return Mod;}
};

using mint=ModInt<1000000007>;

signed main(){
    int n,m;cin>>n>>m;n++;
    Graph<ll> g(n);
    vector<ll> a(m);
    rep(i,m){
        int u,v;ll w;cin>>u>>v>>w>>a[i];
        g.add_directed_edge(u,v,w);
    }

    cout<<"INF"<<endl;
    return 0;

    // INF?
    {
        StronglyConnectedComponents scc(g);
        vector<bool> check(scc.compressed.size(),true);
        for(int i=scc.belong[0];i<(int)scc.compressed.size();i++){
            if(scc.group[i].size()>1) check[i]=false;
            if(!check[i])for(auto j:scc.compressed[i]) check[j]=false;
        }
        if(!check[scc.belong[n-1]]){
            cout<<"INF"<<endl;
            return 0;
        }
    }

    vector<mint> dp(n,0);
    vector<bool> check(n,false);
    function<void(int)> dfs=[&](int cur){
        check[cur]=true;
        for(auto &e:g[cur]){
            if(!check[e]){
                dp[e]+=(dp[cur]+e.w)*a[e.idx];
            }
        }
        for(auto &e:g[cur])if(!check[e])dfs(e);
    };

    dfs(0);

    // debug(dp);
    cout<<dp[n-1]<<endl;
    return 0;
}