import java.util.Arrays;

public class Main {

  private static void solve() {
    int n = ni();
    int m = ni();
    int p = ni();
    int[] from = new int[m];
    int[] to = new int[m];
    int[] w = new int[m];
    for (int i = 0; i < m; i++) {
      from[i] = ni() - 1;
      to[i] = ni() - 1;
      w[i] = p - ni();
    }

    long[] d = bf(from, to, w, n, 0);
    if (d[n - 1] >= Long.MAX_VALUE / 3) {
      System.out.println(-1);
    } else {
      System.out.println(Math.max(0, -d[n - 1]));

    }
  }

  public static long[] bf(int[] from, int[] to, int[] w, int n, int start) {
    long[] d = new long[n];
    Arrays.fill(d, Long.MAX_VALUE / 2);
    d[start] = 0;
    int m = from.length;

    boolean[] loop = new boolean[m];
    for (int r = 0; r < n * 2; r++) {
      boolean updated = false;
      for (int j = 0; j < m; j++) {
        if (d[from[j]] + w[j] < d[to[j]]) {
          d[to[j]] = d[from[j]] + w[j];
          updated = true;
          if (r >= n) {
            loop[j] = true;
          }
        }
      }
      if (!updated)
        break;
    }

    for (int i = 0; i < m; i++) {
      if (loop[i]) {
        d[from[i]] = Long.MAX_VALUE / 3;
        d[to[i]] = Long.MAX_VALUE / 3;
      }
    }

    return d;
  }

  public static int[][][] packWD(int n, int[] from, int[] to, int[] w) {
    int[][][] g = new int[n][][];
    int[] p = new int[n];
    for (int f : from)
      p[f]++;
    for (int i = 0; i < n; i++)
      g[i] = new int[p[i]][2];
    for (int i = 0; i < from.length; i++) {
      --p[from[i]];
      g[from[i]][p[from[i]]][0] = to[i];
      g[from[i]][p[from[i]]][1] = w[i];
    }
    return g;
  }



  public static void main(String[] args) {
    new Thread(null, new Runnable() {
      @Override
      public void run() {
        long start = System.currentTimeMillis();
        String debug = args.length > 0 ? args[0] : null;
        if (debug != null) {
          try {
            is = java.nio.file.Files.newInputStream(java.nio.file.Paths.get(debug));
          } catch (Exception e) {
            throw new RuntimeException(e);
          }
        }
        reader = new java.io.BufferedReader(new java.io.InputStreamReader(is), 32768);
        solve();
        out.flush();
        tr((System.currentTimeMillis() - start) + "ms");
      }
    }, "", 64000000).start();
  }

  private static java.io.InputStream is = System.in;
  private static java.io.PrintWriter out = new java.io.PrintWriter(System.out);
  private static java.util.StringTokenizer tokenizer = null;
  private static java.io.BufferedReader reader;

  public static String next() {
    while (tokenizer == null || !tokenizer.hasMoreTokens()) {
      try {
        tokenizer = new java.util.StringTokenizer(reader.readLine());
      } catch (Exception e) {
        throw new RuntimeException(e);
      }
    }
    return tokenizer.nextToken();
  }

  private static double nd() {
    return Double.parseDouble(next());
  }

  private static long nl() {
    return Long.parseLong(next());
  }

  private static int[] na(int n) {
    int[] a = new int[n];
    for (int i = 0; i < n; i++)
      a[i] = ni();
    return a;
  }

  private static char[] ns() {
    return next().toCharArray();
  }

  private static long[] nal(int n) {
    long[] a = new long[n];
    for (int i = 0; i < n; i++)
      a[i] = nl();
    return a;
  }

  private static int[][] ntable(int n, int m) {
    int[][] table = new int[n][m];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        table[i][j] = ni();
      }
    }
    return table;
  }

  private static int[][] nlist(int n, int m) {
    int[][] table = new int[m][n];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        table[j][i] = ni();
      }
    }
    return table;
  }

  private static int ni() {
    return Integer.parseInt(next());
  }

  private static void tr(Object... o) {
    if (is != System.in)
      System.out.println(java.util.Arrays.deepToString(o));
  }
}



Measured memory_bytes: 28404