//@formatter:off
#include<bits/stdc++.h>
#define overload4(_1,_2,_3,_4,name,...) name
#define rep1(i,n) for (ll i = 0; i < ll(n); ++i)
#define rep2(i,s,n) for (ll i = ll(s); i < ll(n); ++i)
#define rep3(i,s,n,d) for(ll i = ll(s); i < ll(n); i+=d)
#define rep(...) overload4(__VA_ARGS__,rep3,rep2,rep1)(__VA_ARGS__)
#define rrep(i,n) for (ll i = ll(n)-1; i >= 0; i--)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define pb push_back
#define eb emplace_back
#ifdef __LOCAL
#define debug(...) { cout << #__VA_ARGS__; cout << ": "; print(__VA_ARGS__); cout << flush; }
#else
#define debug(...) void(0)
#endif
#define INT(...) int __VA_ARGS__;scan(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__;scan(__VA_ARGS__)
#define STR(...) string __VA_ARGS__;scan(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__;scan(__VA_ARGS__)
#define DBL(...) double __VA_ARGS__;scan(__VA_ARGS__)
#define LD(...) ld __VA_ARGS__;scan(__VA_ARGS__)
using namespace std;
using ll = long long;
using ld = long double;
using P = pair<int,int>;
using LP = pair<ll,ll>;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vl = vector<ll>;
using vvl = vector<vector<ll>>;
using vd = vector<double>;
using vvd = vector<vector<double>>;
using vs = vector<string>;
using vc = vector<char>;
using vvc = vector<vector<char>>;
using vb = vector<bool>;
using vvb = vector<vector<bool>>;
using vp = vector<P>;
using vvp = vector<vector<P>>;
template<class S,class T> istream& operator>>(istream &is,pair<S,T> &p) { return is >> p.first >> p.second; }
template<class S,class T> ostream& operator<<(ostream &os,const pair<S,T> &p) { return os<<'{'<<p.first<<","<<p.second<<'}'; }
template<class T> istream& operator>>(istream &is,vector<T> &v) { for(T &t:v){is>>t;} return is; }
template<class T> ostream& operator<<(ostream &os,const vector<T> &v) { os<<'[';rep(i,v.size())os<<v[i]<<(i==int(v.size()-1)?"":","); return os<<']'; }
template<class T> bool chmin(T& a,T b) {if(a > b){a = b; return true;} return false;}
template<class T> bool chmax(T& a,T b) {if(a < b){a = b; return true;} return false;}
void scan(){}
template <class Head, class... Tail> void scan(Head& head, Tail&... tail){ cin >> head; scan(tail...); }
template<class T> void print(const T& t){ cout << t << '\n'; }
template <class Head, class... Tail> void print(const Head& head, const Tail&... tail){ cout<<head<<' '; print(tail...); }
template<class T> void fin(T a) { print(a); exit(0); }
const string yes[] = {"no","yes"};
const string Yes[] = {"No","Yes"};
const string YES[] = {"NO","YES"};
const int inf = 1001001001;
const ll linf = 1001001001001001001;
//@formatter:on

constexpr int mod = 1000000007;

//constexpr int mod = 998244353;
struct mint {
    ll x;
    
    constexpr mint(ll x = 0) : x((x % mod + mod) % mod) {}
    
    constexpr mint operator-() const { return mint(-x); }
    
    constexpr mint &operator+=(const mint &a) {
        if ((x += a.x) >= mod) x -= mod;
        return *this;
    }
    
    constexpr mint &operator++() { return *this += mint(1); }
    
    constexpr mint &operator-=(const mint &a) {
        if ((x += mod - a.x) >= mod) x -= mod;
        return *this;
    }
    
    constexpr mint &operator--() { return *this -= mint(1); }
    
    constexpr mint &operator*=(const mint &a) {
        (x *= a.x) %= mod;
        return *this;
    }
    
    constexpr mint operator+(const mint &a) const {
        mint res(*this);
        return res += a;
    }
    
    constexpr mint operator-(const mint &a) const {
        mint res(*this);
        return res -= a;
    }
    
    constexpr mint operator*(const mint &a) const {
        mint res(*this);
        return res *= a;
    }
    
    constexpr mint pow(ll t) const {
        mint res = mint(1), a(*this);
        while (t > 0) {
            if (t & 1) res *= a;
            t >>= 1;
            a *= a;
        }
        return res;
    }
    
    // for prime mod
    constexpr mint inv() const { return pow(mod - 2); }
    
    constexpr mint &operator/=(const mint &a) { return *this *= a.inv(); }
    
    constexpr mint operator/(const mint &a) const {
        mint res(*this);
        return res /= a;
    }
};

ostream &operator<<(ostream &os, const mint &a) { return os << a.x; }

bool operator==(const mint &a, const mint &b) { return a.x == b.x; }

bool operator!=(const mint &a, const mint &b) { return a.x != b.x; }

bool operator==(const mint &a, const int &b) { return a.x == b; }

bool operator!=(const mint &a, const int &b) { return a.x != b; }

struct edge {
    int to, l, a;
    
    edge(int to, int l, int a) : to(to), l(l), a(a) {}
};

mint dp[100010];
mint cnt[100010];

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    INT(n, m);
    n++;
    vector<vector<edge>> G(n);
    vector<vector<edge>> rG(n);
    rep(_, m) {
        INT(u, v, l, a);
        G[u].eb(v, l, a);
        rG[v].eb(u, l, a);
    }
    vb ok(n, false);
    ok[n - 1] = true;
    queue<int> q;
    q.push(n - 1);
    while (!q.empty()) {
        int u = q.front();
        q.pop();
        for (auto &e : rG[u]) {
            if (ok[e.to]) continue;
            ok[e.to] = true;
            q.push(e.to);
        }
    }
    if (!ok[0]) fin(0);
    vb nok(n, false);
    nok[0] = true;
    q.push(0);
    while (!q.empty()) {
        int u = q.front();
        q.pop();
        for (auto &e : G[u]) {
            if (nok[e.to]) continue;
            nok[e.to] = true;
            q.push(e.to);
        }
    }
    assert(nok[n - 1]);
    rep(i, n) ok[i] = ok[i] & nok[i];
    vi in(n);
    int sz = 0;
    rep(i, n) {
        if (!ok[i]) continue;
        sz++;
        for (auto &e : G[i]) {
            if (!ok[e.to]) continue;
            in[e.to]++;
        }
    }
    vi ord;
    rep(i, n) if (ok[i] and !in[i]) q.push(i);
    while (!q.empty()) {
        int u = q.front();
        assert(ok[u]);
        q.pop();
        ord.pb(u);
        for (auto &e : G[u]) {
            if (!ok[e.to]) continue;
            if (--in[e.to] == 0) q.push(e.to);
        }
    }
    if (ord.size() < sz) fin("INF");
    assert(ord.size() == sz);
    assert(ord[0] == 0);
    assert(ord.back() == n - 1);
    vi pos(n, -1);
    rep(i, sz) pos[ord[i]] = i;
    cnt[0] = 1;
    rep(i, sz) {
        if (cnt[i] == 0) continue;
        int now = ord[i];
        for (auto &e : G[now]) {
            if (!ok[e.to]) continue;
            int nx = pos[e.to];
            assert(nx > i);
            cnt[nx] += cnt[i] * e.a;
            dp[nx] += dp[i] * e.a + cnt[i] * e.a * e.l;
        }
    }
    print(dp[sz - 1]);
}