using System;
using System.Collections.Generic;
using System.Linq;
using Debug = System.Diagnostics.Debug;
//using System.Numerics;
//using static System.Math;
using Number = System.Int64;

namespace Program {
    public class Solver {
        //const long MOD = (long)1e9 + 7;
        public void Solve() {
            var n = ri;
            var m = ri;
            var f = new int[m];
            var t = new int[m];
            var w = new int[m];
            var s = new DisjointSet(n);
            var g = new SCCGraph(n);
            var G = Enumerate(n, x => new List<int>());
            var ok = true;
            for (int i = 0; i < m; i++) {
                f[i] = ri - 1; t[i] = ri - 1; w[i] = ri;
                G[f[i]].Add(t[i]);
                if (w[i] == 2) {
                    ok &= s.Unite(f[i], t[i]);
                    G[t[i]].Add(f[i]);
                }
            }
            for (int i = 0; i < m; i++)
                if (w[i] == 1) g.AddEdge(s[f[i]], s[t[i]]);
            g.Build();
            for (int i = 0; i < g.Count; i++)
                ok &= g.scc[i].Count == 1;
            if (!ok) { Console.WriteLine("Infinite"); return; }

            var dp = Enumerate(n, x => -1);
            Func<int, int, int> dfs = null;
            Action<int, int, int> efs = null;

            dfs = (prev, cur) => {
                if (dp[cur] != -1) return dp[cur];
                var ret = 0;
                var root = prev == -1 || !s.IsUnited(prev, cur);
                foreach (var to in G[cur]) {
                    if (prev == to) continue;
                    ret = Math.Max(ret, 1 + dfs(cur, to));
                }
                if (root) efs(-1, cur, -1000000);
                return dp[cur] = ret;
            };
            efs = (prev, cur, max) => {
                //Debug.WriteLine($"efs {prev} {cur} {max}");
                var d = G[cur].Count;
                var dpv = new int[d + 1];
                var dpR = new int[d + 1];
                for (int i = 0; i < d; i++)
                    if (G[cur][i] != prev) dpv[i] = 1 + dp[G[cur][i]];
                    else dpv[i] = 1 + max;
                for (int i = d - 1; i >= 0; i--)
                    dpR[i] = Math.Max(dpR[i + 1], dpv[i]);
                var vl = 0;
                for (int i = 0; i < d; i++) {
                    if (G[cur][i] != prev && s.IsUnited(cur, G[cur][i])) {
                        efs(cur, G[cur][i], Math.Max(vl, dpR[i + 1]));
                    }
                    vl = Math.Max(vl, dpv[i]);
                }
                dp[cur] = vl;
            };
            var ans = 0;
            for (int i = 0; i < n; i++) ans = Math.Max(ans, dfs(-1, i));
            Debug.WriteLine(dp.AsJoinedString());
            Console.WriteLine(ans);
        }

        const long INF = 1L << 60;
        //int[] dx = { 1, 0, -1, 0 };
        //int[] dy = { 0, 1, 0, -1 };
        //*
        int ri { get { return sc.Integer(); } }
        long rl { get { return sc.Long(); } }
        double rd { get { return sc.Double(); } }
        string rs { get { return sc.Scan(); } }
        //*/

        public IO.StreamScanner sc = new IO.StreamScanner(Console.OpenStandardInput());
        static T[] Enumerate<T>(int n, Func<int, T> f) { var a = new T[n]; for (int i = 0; i < n; ++i) a[i] = f(i); return a; }
        static public void Swap<T>(ref T a, ref T b) { var tmp = a; a = b; b = tmp; }
    }
}

#region main
static class Ex {
    static public string AsString(this IEnumerable<char> ie) { return new string(ie.ToArray()); }
    static public string AsJoinedString<T>(this IEnumerable<T> ie, string st = " ") {
        return string.Join(st, ie.Select(x => x.ToString()).ToArray());
        //return string.Join(st, ie);
    }
    static public void Main() {
        Console.SetOut(new System.IO.StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
        var solver = new Program.Solver();
        solver.Solve();
        Console.Out.Flush();
    }
}
#endregion
#region Ex
namespace Program.IO {
    using System.Globalization;
    using System.IO;
    using System.Text;
    public class Printer: StreamWriter {
        public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } }
        public Printer(Stream stream) : base(stream, new UTF8Encoding(false, true)) { }
    }
    public class StreamScanner {
        public StreamScanner(Stream stream) { str = stream; }
        public readonly Stream str;
        private readonly byte[] buf = new byte[1024];
        private int len, ptr;
        public bool isEof = false;
        public bool IsEndOfStream { get { return isEof; } }
        private byte read() {
            if (isEof) return 0;
            if (ptr >= len) { ptr = 0; if ((len = str.Read(buf, 0, 1024)) <= 0) { isEof = true; return 0; } }
            return buf[ptr++];
        }
        public char Char() { byte b = 0; do b = read(); while ((b < 33 || 126 < b) && !isEof); return (char)b; }

        public string Scan() {
            var sb = new StringBuilder();
            for (var b = Char(); b >= 33 && b <= 126; b = (char)read())
                sb.Append(b);
            return sb.ToString();
        }
        public string ScanLine() {
            var sb = new StringBuilder();
            for (var b = Char(); b != '\n' && b != 0; b = (char)read())
                if (b != '\r') sb.Append(b);
            return sb.ToString();
        }
        public long Long() { return isEof ? long.MinValue : long.Parse(Scan()); }
        public int Integer() { return isEof ? int.MinValue : int.Parse(Scan()); }
        public double Double() { return isEof ? double.NaN : double.Parse(Scan(), CultureInfo.InvariantCulture); }
    }
}
#endregion

#region DisjointSet
public class DisjointSet {
    int[] par;
    byte[] rank;
    public DisjointSet(int n) {
        par = new int[n];
        for (int i = 0; i < n; i++)
            par[i] = -1;
        rank = new byte[n];
    }
    public int this[int id] {
        get {
            if ((par[id] < 0)) return id;
            return par[id] = this[par[id]];
        }
    }
    public bool Unite(int x, int y) {
        x = this[x]; y = this[y];
        if (x == y) return false;
        if (rank[x] < rank[y]) { var z = x; x = y; y = z; }
        par[x] += par[y];
        par[y] = x;
        if (rank[x] == rank[y])
            rank[x]++;
        return true;
    }
    public int Size(int x) { return -par[this[x]]; }
    public bool IsUnited(int x, int y) { return this[x] == this[y]; }

}
#endregion

#region SCCGraph
public class SCCGraph {
    int n;

    List<int>[] g;
    public List<List<int>> scc;
    int[] group;

    /// <summary>
    /// ?????£?????????????????????
    /// </summary>
    public int Count { get; private set; }

    public SCCGraph(int N) {
        n = N;
        g = new List<int>[n];
        scc = new List<List<int>>();
        for (int i = 0; i < n; i++)
            g[i] = new List<int>();
    }
    public void AddEdge(int f, int t) { g[f].Add(t); }
    public int this[int id] { get { return group[id]; } }
    public void Build() {
        Decomposite();
        scc.Reverse();
        group = new int[n];
        for (int i = 0; i < Count; i++)
            foreach (var x in scc[i]) group[x] = i;

    }
    /// <summary>
    /// ?????£?????????????§£?????????
    /// </summary>
    public int Decomposite() {
        var S = new Stack<int>(n + 2);
        var B = new Stack<int>(n + 2);
        var I = new int[n];
        var iter = new int[n];
        var s = new Stack<int>(n + 2);
        for (int i = 0; i < n; i++) {
            if (I[i] != 0) continue;
            s.Push(i);
            while (s.Count > 0) {
                DFS:
                var u = s.Peek();
                if (I[u] == 0) {
                    B.Push(I[u] = S.Count);
                    S.Push(u);
                    iter[u] = 0;
                }
                while (iter[u] < g[u].Count) {
                    var v = g[u][iter[u]++];
                    if (I[v] == 0) {
                        s.Push(v);
                        goto DFS;
                    }
                    else while (I[v] < B.Peek()) B.Pop();
                }
                if (I[u] == B.Peek()) {
                    var ns = new List<int>();
                    scc.Add(ns);
                    B.Pop();
                    while (I[u] < S.Count) {
                        var p = S.Pop();
                        ns.Add(p);
                        I[p] = n + scc.Count;
                    }
                }
                s.Pop();

            }
        }
        return Count = scc.Count;

    }
    public bool IsSameGroup(int u, int v) { return group[u] == group[v]; }
}
#endregion


Measured memory_bytes: 56436