using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;

using E = System.Linq.Enumerable;

using CostType = System.Int64;

internal partial class Solver {
    public void Run() {
        var n = ni();
        var m = ni();
        var p = ni();
        var g = new WeightedDirectedGraph(n);
        for (int i = 0; i < m; i++) {
            var a = ni() - 1;
            var b = ni() - 1;
            var c = ni();
            g.AddEdge(a, b, p - c);
        }
        var ans = g.BellmanFord(0)[n - 1];
        if (ans == CostType.MinValue) {
            ans = -1;
        } else {
            ans = Math.Max(0, -ans);
        }
        cout.WriteLine(ans);
    }
}


public class WeightedDirectedGraph {
    public struct Edge {
        public int From { get; set; }
        public int To { get; set; }
        public CostType Cost { get; set; }
    }
    private readonly List<Edge>[] _adj;
    public WeightedDirectedGraph(int n) {
        _adj = Enumerable.Range(0, n).Select(_ => new List<Edge>()).ToArray();
    }

    public void AddEdge(int from, int to, CostType cost) {
        _adj[from].Add(new Edge { From = from, To = to, Cost = cost });
    }

    public IEnumerable<Edge> this[int index] {
        get { return _adj[index]; }
    }

    public int VertexCount { get { return _adj.Length; } }
}

public static partial class ShortestPathExtension {
    public static ShorestPathInfo BellmanFord(this WeightedDirectedGraph graph, int start) {
        var n = graph.VertexCount;
        var dist = new CostType[n];
        var prev = Enumerable.Repeat(-1, n).ToArray();
        var inf = CostType.MaxValue;
        var negativeInf = CostType.MinValue;
        for (int i = 0; i < n; i++) dist[i] = inf;
        dist[start] = 0;
        for (int i = 0; i <= n; i++) {
            bool updated = false;
            for (int j = 0; j < n; j++) {
                foreach (var e in graph[j]) {
                    var newCost = dist[e.From];
                    if (newCost != inf) {
                        if (newCost != negativeInf) newCost += e.Cost;
                        if (dist[e.To] > newCost) {
                            prev[e.To] = e.From;
                            dist[e.To] = i >= n ? negativeInf : newCost;
                            updated = true;
                        }
                    }
                }
            }
            if (!updated) break;
        }
        var queue = new Queue<int>();
        var visited = new bool[n];
        for (int i = 0; i < n; i++) {
            if (dist[i] == negativeInf) {
                queue.Enqueue(i);
            }
        }
        while (queue.Count > 0) {
            var now = queue.Dequeue();
            if (visited[now]) continue;
            visited[now] = true;
            dist[now] = negativeInf;
            foreach (var e in graph[now]) {
                if (!visited[e.To]) {
                    queue.Enqueue(e.To);
                }
            }
        }

        return new ShorestPathInfo(dist, prev);
    }


    public static ShorestPathInfo SPFA(this WeightedDirectedGraph graph, int start) {
        var n = graph.VertexCount;
        var inf = CostType.MaxValue;
        var negativeInf = CostType.MinValue;
        var dist = Enumerable.Repeat(inf, n).ToArray();
        var prev = Enumerable.Repeat(-1, n).ToArray();
        var inQueue = new bool[n];
        var visitedNum = new int[n];
        var qu = new Queue<int>();
        dist[start] = 0;
        visitedNum[start]++;
        inQueue[start] = true;
        qu.Enqueue(start);
        while (qu.Count > 0) {
            var pos = qu.Dequeue();
            inQueue[pos] = false;
            foreach (var edge in graph[pos]) {
                if (dist[pos] != inf && dist[edge.To] > dist[pos] + edge.Cost) {
                    dist[edge.To] = dist[pos] + edge.Cost;
                    prev[edge.To] = pos;
                    if (!inQueue[edge.To]) {
                        if (++visitedNum[edge.To] < n) {
                            inQueue[edge.To] = true;
                            qu.Enqueue(edge.To);
                        }
                    }
                }
            }
        }
        var queue = new Queue<int>();
        for (int i = 0; i < n; i++) {
            if (visitedNum[i] >= n) {
                queue.Enqueue(i);
            }
        }
        while (queue.Count > 0) {
            var now = queue.Dequeue();
            if (dist[now] == negativeInf) continue;
            dist[now] = negativeInf;
            foreach (var e in graph[now]) {
                if (dist[e.To] != negativeInf) {
                    queue.Enqueue(e.To);
                }
            }
        }
        return new ShorestPathInfo(dist, prev);
    }
}

public class ShorestPathInfo {
    private readonly CostType[] _dist;
    private readonly int[] _prev;
    public ShorestPathInfo(CostType[] dist, int[] prev) {
        _dist = dist;
        _prev = prev;
    }
    public CostType this[int index] {
        get { return _dist[index]; }
    }
    public IEnumerable<int> GetPath(int to) {
        int current = to;
        var path = new List<int>();
        do {
            path.Add(current);
            current = _prev[current];
        } while (current >= 0);
        path.Reverse();
        return path;
    }
}

// PREWRITEN CODE BEGINS FROM HERE
internal partial class Solver : Scanner {
    public static void Main(string[] args) {
#if LOCAL
        new Solver(Console.In, Console.Out).Run();
#else
        Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
        new Solver(Console.In, Console.Out).Run();
        Console.Out.Flush();
#endif
    }

#pragma warning disable IDE0052
    private readonly TextReader cin;
    private readonly TextWriter cout;
#pragma warning restore IDE0052

    public Solver(TextReader reader, TextWriter writer)
        : base(reader) {
        cin = reader;
        cout = writer;
    }
    public Solver(string input, TextWriter writer)
        : this(new StringReader(input), writer) {
    }

#pragma warning disable IDE1006
#pragma warning disable IDE0051
    private int ni() { return NextInt(); }
    private int[] ni(int n) { return NextIntArray(n); }
    private long nl() { return NextLong(); }
    private long[] nl(int n) { return NextLongArray(n); }
    private double nd() { return NextDouble(); }
    private double[] nd(int n) { return NextDoubleArray(n); }
    private string ns() { return Next(); }
    private string[] ns(int n) { return NextArray(n); }
#pragma warning restore IDE1006
#pragma warning restore IDE0051
}

internal static class LinqPadExtension {
    public static T Dump<T>(this T obj) {
#if LOCAL
        return LINQPad.Extensions.Dump(obj);
#else
        return obj;
#endif
    }
}

public class Scanner {
    private readonly TextReader Reader;
    private readonly Queue<string> TokenQueue = new Queue<string>();
    private readonly CultureInfo ci = CultureInfo.InvariantCulture;

    public Scanner()
        : this(Console.In) {
    }

    public Scanner(TextReader reader) {
        Reader = reader;
    }

    public int NextInt() { return int.Parse(Next(), ci); }
    public long NextLong() { return long.Parse(Next(), ci); }
    public double NextDouble() { return double.Parse(Next(), ci); }
    public string[] NextArray(int size) {
        string[] array = new string[size];
        for (int i = 0; i < size; i++) {
            array[i] = Next();
        }

        return array;
    }
    public int[] NextIntArray(int size) {
        int[] array = new int[size];
        for (int i = 0; i < size; i++) {
            array[i] = NextInt();
        }

        return array;
    }

    public long[] NextLongArray(int size) {
        long[] array = new long[size];
        for (int i = 0; i < size; i++) {
            array[i] = NextLong();
        }

        return array;
    }

    public double[] NextDoubleArray(int size) {
        double[] array = new double[size];
        for (int i = 0; i < size; i++) {
            array[i] = NextDouble();
        }

        return array;
    }

    public string Next() {
        if (TokenQueue.Count == 0) {
            if (!StockTokens()) {
                throw new InvalidOperationException();
            }
        }
        return TokenQueue.Dequeue();
    }

    public bool HasNext() {
        if (TokenQueue.Count > 0) {
            return true;
        }

        return StockTokens();
    }

    private static readonly char[] _separator = new[] { ' ', '\t' };
    private bool StockTokens() {
        while (true) {
            string line = Reader.ReadLine();
            if (line == null) {
                return false;
            }

            string[] tokens = line.Split(_separator, StringSplitOptions.RemoveEmptyEntries);
            if (tokens.Length == 0) {
                continue;
            }

            foreach (string token in tokens) {
                TokenQueue.Enqueue(token);
            }

            return true;
        }
    }
}


Measured memory_bytes: 47568