#pragma GCC target("avx2") #pragma GCC optimize("Ofast") #pragma GCC optimize("unroll-loops") #include //#include using namespace std; //using namespace atcoder; #define DEBUG #ifdef DEBUG template ostream &operator<<(ostream &os, const pair &p) { os << '(' << p.first << ',' << p.second << ')'; return os; } template ostream &operator<<(ostream &os, const vector &v) { os << '{'; for(int i = 0; i < (int)v.size(); i++) { if(i) { os << ','; } os << v[i]; } os << '}'; return os; } void debugg() { cerr << endl; } template void debugg(const T &x, const Args &... args) { cerr << " " << x; debugg(args...); } #define debug(...) \ cerr << __LINE__ << " [" << #__VA_ARGS__ << "]: ", debugg(__VA_ARGS__) #define dump(x) cerr << __LINE__ << " " << #x << " = " << (x) << endl #else #define debug(...) (void(0)) #define dump(x) (void(0)) #endif using namespace std; typedef long long ll; typedef vector vl; typedef vector vvl; typedef vector vc; typedef vector vs; typedef vector vb; typedef vector vd; typedef pair P; typedef pair pii; typedef vector

vpl; typedef tuple tapu; #define rep(i,n) for(int i=0; i<(n); i++) #define REP(i,a,b) for(int i=(a); i<(b); i++) #define all(x) (x).begin(), (x).end() #define rall(x) (x).rbegin(), (x).rend() const int inf = (1<<30) - 1; const ll linf = 1LL<<61; const int MAX = 510000; int dy[8] = {0,1,0,-1,1,-1,-1,1}; int dx[8] = {-1,0,1,0,1,-1,1,-1}; const double pi = acos(-1); const double eps = 1e-7; template inline bool chmin(T1 &a,T2 b){ if(a>b){ a = b; return true; } else return false; } template inline bool chmax(T1 &a,T2 b){ if(a inline void print(T &a){ int sz = a.size(); for(auto itr = a.begin(); itr != a.end(); itr++){ cout << *itr; sz--; if(sz) cout << " "; } cout << "\n"; } template inline void print2(T1 a, T2 b){ cout << a << " " << b << "\n"; } template inline void print3(T1 a, T2 b, T3 c){ cout << a << " " << b << " " << c << "\n"; } void mark() {cout << "#" << "\n";} ll pcount(ll x) {return __builtin_popcountll(x);} const int mod = 1e9 + 7; //const int mod = 998244353; template struct ModInt { int x; ModInt() : x(0) {} ModInt(int64_t 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(int64_t 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) { int64_t t; is >> t; a = ModInt(t); return (is); } static int get_mod() { return mod; } }; using mint = ModInt; struct edge{ ll to,l,a; }; int main(){ int n,m; cin >> n >> m; vector> G(n+1), rG(n+1); rep(i,m){ ll u,v,l,a; cin >> u >> v >> l >> a; rG[v].push_back({u,l,a}); } vb visit(n+1,false); visit[n] = true; queue q; q.push(n); while(!q.empty()){ int u = q.front(); q.pop(); for(auto v : rG[u]){ if(visit[v.to]) continue; visit[v.to] = true; q.push(v.to); } } if(!visit[0]){ cout << 0 << "\n"; return 0; } vl indeg(n+1,0); rep(i,n+1){ if(visit[i]){ for(auto e : rG[i]){ G[e.to].push_back({i,e.l,e.a}); indeg[i]++; } } } vector num(n+1,0); rep(i,n+1) if(visit[i] && indeg[i] == 0){ num[i] = 1; q.push(i); } mint ans = 0; while(!q.empty()){ int u = q.front(); q.pop(); for(auto v : G[u]){ num[v.to] += num[u] * v.a; indeg[v.to]--; if(indeg[v.to] == 0){ q.push(v.to); } } } if(accumulate(all(indeg),0LL)){ cout << "INF\n"; return 0; } rG.clear(); rG.resize(n+1); rep(i,n+1){ for(auto v : G[i]){ rG[v.to].push_back({i,v.l,v.a}); indeg[i]++; } } vector num2(n+1,0); rep(i,n+1){ if(visit[i] && indeg[i] == 0){ num2[i] = 1; q.push(i); } } while(!q.empty()){ int u = q.front(); q.pop(); for(auto v : rG[u]){ num2[v.to] += num2[u] * v.a; indeg[v.to]--; if(indeg[v.to] == 0){ q.push(v.to); } } } if(accumulate(all(indeg),0LL)) cout << "INF\n"; else{ rep(i,n+1){ for(auto v : G[i]){ ans += num[i] * num2[v.to] * v.a * v.l; } } } cout << ans << "\n"; }