import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.util.ArrayList;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author caoash
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        ECoinsRespawn solver = new ECoinsRespawn();
        solver.solve(1, in, out);
        out.close();
    }

    static class ECoinsRespawn {
        ArrayList<Edge> e;
        long[] d;
        boolean[] bad;

        public void solve(int testNumber, FastScanner br, PrintWriter pw) {
            int N = br.nextInt();
            int M = br.nextInt();
            int P = br.nextInt();
            e = new ArrayList<Edge>();
            for (int i = 0; i < M; i++) {
                int u = br.nextInt();
                int v = br.nextInt();
                long w = br.nextLong();
                w -= P;
                w *= -1;
                u--;
                v--;
                e.add(new Edge(u, v, w));
            }
            bad = new boolean[N + 1];
            d = new long[N + 1];
            for (int i = 1; i <= N; i++) {
                d[i] = Long.MAX_VALUE;
                bad[i] = false;
            }
            d[0] = 0;
            for (int i = 0; i < N; i++) {
                for (Edge to : e) {
                    if (d[to.a] < Long.MAX_VALUE)
                        d[to.b] = Math.min(d[to.b], d[to.a] + to.cost);
                }
            }
            for (Edge to : e) {
                if (d[to.a] < Long.MAX_VALUE) {
                    if (d[to.b] > d[to.a] + to.cost) {
                        bad[to.b] = true;
                    }
                }
            }

            for (int i = 0; i < N; i++) {
                for (Edge to : e) {
                    if (bad[to.a]) {
                        bad[to.b] = true;
                    }
                }
            }

            if (bad[N - 1]) {
                pw.println(-1);
            } else {
                pw.println(Math.max(0, -1 * d[N - 1]));
            }
            pw.close();
        }

        public class Edge {
            int a;
            int b;
            long cost;

            public Edge(int a, int b, long cost) {
                this.a = a;
                this.b = b;
                this.cost = cost;
            }

        }

    }

    static class FastScanner {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private FastScanner.SpaceCharFilter filter;

        public FastScanner(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public int nextInt() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public long nextLong() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }
}



Measured memory_bytes: 24916