using System; using System.Collections.Generic; using System.Linq; using System.IO; using System.Threading; using System.Text; using System.Text.RegularExpressions; using System.Diagnostics; using static util; using P = pair; class Program { static void Main(string[] args) { var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false }; var solver = new Solver(sw); // var t = new Thread(solver.solve, 1 << 28); // 256 MB // t.Start(); // t.Join(); solver.solve(); sw.Flush(); } } class Solver { StreamWriter sw; Scan sc; void Prt(string a) => sw.WriteLine(a); void Prt(IEnumerable a) => Prt(string.Join(" ", a)); void Prt(params object[] a) => Prt(string.Join(" ", a)); public Solver(StreamWriter sw) { this.sw = sw; this.sc = new Scan(); } public void solve() { int n, m; sc.Multi(out n, out m); ++n; var ed = new List[n]; var edg = new List, int>>[n]; for (int i = 0; i < n; i++) { ed[i] = new List(); edg[i] = new List, int>>(); } for (int i = 0; i < m; i++) { int u, v, l, a; sc.Multi(out u, out v, out l, out a); ed[u].Add(v); edg[u].Add(new pair, int>(new pair(l, a), v)); } var cmp = Scc.scc(ed, out _); int N = cmp.Max() + 1; var edge = new List, int>>[N]; for (int i = 0; i < N; i++) { edge[i] = new List, int>>(); } var self = new bool[N]; for (int i = 0; i < n; i++) { foreach (var ((l, a), v) in edg[i]) { if (cmp[i] != cmp[v]) { edge[cmp[i]].Add(new pair, int>(new pair(l, a), cmp[v])); } else { self[cmp[i]] = true; } } } var dp = new pair[N]; var vis = new bool[N]; for (int i = 0; i < N; i++) { dp[i] = new pair(0, 0); } dp[cmp[0]] = new pair(0, 1); vis[cmp[0]] = true; for (int i = 0; i < N; i++) { if (!vis[i]) continue; if (self[i]) dp[i].v1 = -1; foreach (var ((l, a), v) in edge[i]) { if (dp[v].v1 == -1) continue; if (dp[i].v1 == -1) { dp[v].v1 = -1; continue; } dp[v].v1 = (dp[v].v1 + dp[i].v1 * a + dp[i].v2 * a % M * l) % M; dp[v].v2 = (dp[v].v2 + dp[i].v2 * a) % M; } } long ans = dp[cmp[n - 1]].v1; if (ans == -1) { Prt("INF"); } else { Prt(ans); } } } class pair : IComparable> { public T v1; public U v2; public pair() : this(default(T), default(U)) {} public pair(T v1, U v2) { this.v1 = v1; this.v2 = v2; } public int CompareTo(pair a) { int c = Comparer.Default.Compare(v1, a.v1); return c != 0 ? c : Comparer.Default.Compare(v2, a.v2); } public override string ToString() => v1 + " " + v2; public void Deconstruct(out T a, out U b) { a = v1; b = v2; } } static class util { public static readonly int M = 1000000007; // public static readonly int M = 998244353; public static readonly long LM = 1L << 60; public static readonly double eps = 1e-11; public static void DBG(string a) => Console.Error.WriteLine(a); public static void DBG(IEnumerable a) => DBG(string.Join(" ", a)); public static void DBG(params object[] a) => DBG(string.Join(" ", a)); public static void Assert(params bool[] conds) { if (conds.Any(x => !x)) throw new Exception(); } public static pair make_pair(T v1, U v2) => new pair(v1, v2); public static int CompareList(IList a, IList b) where T : IComparable { for (int i = 0; i < a.Count && i < b.Count; i++) if (a[i].CompareTo(b[i]) != 0) return a[i].CompareTo(b[i]); return a.Count.CompareTo(b.Count); } public static bool inside(int i, int j, int h, int w) => i >= 0 && i < h && j >= 0 && j < w; public static readonly int[] dd = { 0, 1, 0, -1 }; // static readonly string dstring = "RDLU"; public static IEnumerable

adjacents(int i, int j) { for (int k = 0; k < 4; k++) yield return new P(i + dd[k], j + dd[k ^ 1]); } public static IEnumerable

adjacents(int i, int j, int h, int w) => adjacents(i, j).Where(p => inside(p.v1, p.v2, h, w)); public static IEnumerable

adjacents(this P p) => adjacents(p.v1, p.v2); public static IEnumerable

adjacents(this P p, int h, int w) => adjacents(p.v1, p.v2, h, w); public static IEnumerable all_subset(this int p) { for (int i = 0; ; i = i - p & p) { yield return i; if (i == p) break; } } public static Dictionary compress(this IEnumerable a) => a.Distinct().OrderBy(v => v).Select((v, i) => new { v, i }).ToDictionary(p => p.v, p => p.i); public static Dictionary compress(params IEnumerable[] a) => compress(a.SelectMany(x => x)); public static T[] inv(this Dictionary dic) { var res = new T[dic.Count]; foreach (var item in dic) res[item.Value] = item.Key; return res; } public static void swap(ref T a, ref T b) where T : struct { var t = a; a = b; b = t; } public static void swap(this IList a, int i, int j) where T : struct { var t = a[i]; a[i] = a[j]; a[j] = t; } public static T[] copy(this IList a) { var ret = new T[a.Count]; for (int i = 0; i < a.Count; i++) ret[i] = a[i]; return ret; } } class Scan { StreamReader sr; public Scan() { sr = new StreamReader(Console.OpenStandardInput()); } public Scan(string path) { sr = new StreamReader(path); } public int Int => int.Parse(Str); public long Long => long.Parse(Str); public double Double => double.Parse(Str); public string Str => ReadLine.Trim(); public string ReadLine => sr.ReadLine(); public pair Pair() { T a; U b; Multi(out a, out b); return new pair(a, b); } public P P => Pair(); public int[] IntArr => StrArr.Select(int.Parse).ToArray(); public long[] LongArr => StrArr.Select(long.Parse).ToArray(); public double[] DoubleArr => StrArr.Select(double.Parse).ToArray(); public string[] StrArr => Str.Split(new[]{' '}, StringSplitOptions.RemoveEmptyEntries); bool eq() => typeof(T).Equals(typeof(U)); T ct(U a) => (T)Convert.ChangeType(a, typeof(T)); T cv(string s) => eq() ? ct(int.Parse(s)) : eq() ? ct(long.Parse(s)) : eq() ? ct(double.Parse(s)) : eq() ? ct(s[0]) : ct(s); public void Multi(out T a) => a = cv(Str); public void Multi(out T a, out U b) { var ar = StrArr; a = cv(ar[0]); b = cv(ar[1]); } public void Multi(out T a, out U b, out V c) { var ar = StrArr; a = cv(ar[0]); b = cv(ar[1]); c = cv(ar[2]); } public void Multi(out T a, out U b, out V c, out W d) { var ar = StrArr; a = cv(ar[0]); b = cv(ar[1]); c = cv(ar[2]); d = cv(ar[3]); } public void Multi(out T a, out U b, out V c, out W d, out X e) { var ar = StrArr; a = cv(ar[0]); b = cv(ar[1]); c = cv(ar[2]); d = cv(ar[3]); e = cv(ar[4]); } public void Multi(out T a, out U b, out V c, out W d, out X e, out Y f) { var ar = StrArr; a = cv(ar[0]); b = cv(ar[1]); c = cv(ar[2]); d = cv(ar[3]); e = cv(ar[4]); f = cv(ar[5]); } } static class Scc { public static int[] scc(List[] edge, out List[] cmped_edge) { int n = edge.Length; var vis = new bool[n]; var st = new Stack(); var cmp = new int[n]; for (int i = 0; i < n; i++) if (!vis[i]) dfs(i, -1, vis, st, cmp, edge); vis = new bool[n]; var rev = new List[n]; for (int i = 0; i < n; i++) rev[i] = new List(); for (int i = 0; i < n; i++) foreach (int j in edge[i]) rev[j].Add(i); int k = 0; while (st.Any()) { int i = st.Pop(); if (!vis[i]) dfs(i, k++, vis, new Stack(), cmp, rev); } var cmped_edge_set = new HashSet[k]; for (int i = 0; i < k; i++) cmped_edge_set[i] = new HashSet(); for (int i = 0; i < n; i++) foreach (var item in edge[i]) if (cmp[i] != cmp[item]) cmped_edge_set[cmp[i]].Add(cmp[item]); cmped_edge = new List[k]; for (int i = 0; i < k; i++) cmped_edge[i] = cmped_edge_set[i].ToList(); return cmp; } static void dfs(int v, int k, bool[] vis, Stack st, int[] cmp, List[] edge) { vis[v] = true; cmp[v] = k; foreach (int i in edge[v]) if (!vis[i]) dfs(i, k, vis, st, cmp, edge); st.Push(v); } }