#include<algorithm>
#include<cassert>
#include<tuple>
#include<iostream>
#include<vector>
using namespace std;
typedef long long lint;
typedef vector<int>vi;
typedef pair<int,int>pii;
typedef tuple<int,int,int>tri;
#define rep(i,n)for(int i=0;i<(int)(n);++i)

const lint mod=1e9+7;
const int N=100001;
int n,m;
vector<tri>g[N];
//dp1:通り数,dp2:長さの合計
lint dp1[N],dp2[N];
bool inf[N];
int st[N];

void dfs(int v){
  if(st[v]==1){
    inf[v]=1;
    st[v]=2;
    return;
  }
  if(st[v]==2){
    return;
  }
  st[v]=1;
  dp1[v]=v==n?1:0;
  for(tri wlk:g[v]){
    int w,l,k;
    tie(w,l,k)=wlk;
    
    dfs(w);
    if(inf[w]){
      inf[v]=1;
    }else{
      dp1[v]=(dp1[v]+dp1[w]*k)%mod;
      dp2[v]=(dp2[v]+dp2[w]*k+dp1[w]*k%mod*l)%mod;
    }
  }
  st[v]=2;
}

int main(){
  cin>>n>>m;
  rep(_,m){
    int a,b,l,k;cin>>a>>b>>l>>k;
    g[a].push_back(tri(b,l,k));
  }
  dfs(0);
  if(inf[0]){
    cout<<"INF"<<endl;
    return 0;
  }
  cout<<dp2[0]<<endl;
}