#include<bits/stdc++.h>
using namespace std;
using LL = long long;
using ULL = unsigned long long;
#define rep(i,n) for(int i=0; i<(n); i++)

const ULL M=1000000007;

struct Edge{
  int to;
  ULL d,t;
};

int N,n;
vector<Edge> E[100001];
int I[100001];
vector<int> Ord;
ULL dpc[100001];
ULL dp[100001];

int main() {
  scanf("%d%d",&N,&n); N++;
  rep(i,N) I[i]=0;
  rep(i,n){
    int u,v,d,t; scanf("%d%d%d%d",&u,&v,&d,&t);
    E[u].push_back({v,(ULL)d,(ULL)t});
    I[v]++;
  }
  {
    queue<int> Q; rep(i,N) if(I[i]==0) Q.push(i);
    vector<int> Iin(N);
    while(Q.size()){
      int p=Q.front(); Q.pop();
      Ord.push_back(p);
      Iin[p]=1;
      for(auto& e:E[p]) if((--I[e.to])==0) Q.push(e.to);
    }
    if(Iin[0]==0 || Iin[N-1]==0){ printf("INF\n"); return 0; }
  }
  rep(i,N) dp[i]=dpc[i]=0;
  dpc[0]=1;
  for(int p:Ord){
    for(Edge e:E[p]){
      dpc[e.to] = (dpc[e.to]+dpc[p]*e.t)%M;
      dp[e.to] = (dp[e.to]+(dp[p]+e.d)*e.t)%M;
    }
  }
  printf("%llu\n",dp[N-1]);
  return 0;
}