import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.io.BufferedWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Stream;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.io.InputStream;

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

    static class ECoinsRespawn {
        public void solve(int testNumber, InputReader in, OutputWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            int p = in.nextInt();
            List<Integer>[] g = Stream.generate(ArrayList::new).limit(n).toArray(List[]::new);
            int[] a = new int[m], b = new int[m], c = new int[m];
            for (int i = 0; i < m; i++) {
                a[i] = in.nextInt() - 1;
                b[i] = in.nextInt() - 1;
                c[i] = p - in.nextInt();
                g[a[i]].add(b[i]);
                g[b[i]].add(a[i]);
            }
            int[] dist = new int[n];
            Arrays.fill(dist, 1000 * 1000 * 1000);
            dist[0] = 0;
            for (int j = 0; j < n - 1; j++)
                for (int i = 0; i < m; i++) {
                    if (dist[b[i]] > dist[a[i]] + c[i])
                        dist[b[i]] = dist[a[i]] + c[i];
                }
            int[] curr = dist.clone();

            for (int j = 0; j < n; j++)
                for (int i = 0; i < m; i++) {
                    if (dist[b[i]] > dist[a[i]] + c[i])
                        dist[b[i]] = dist[a[i]] + c[i];
                }

            if (dist[n - 1] != curr[n - 1]) {
                out.println(-1);
            } else {
                if (dist[n - 1] == 1000 * 1000 * 1000) dist[n - 1] = 0;
                out.println(Integer.max(0, -dist[n - 1]));
            }
        }

    }

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

        public InputReader(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 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);

        }

    }

    static class OutputWriter {
        private final PrintWriter writer;

        public OutputWriter(OutputStream outputStream) {
            writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
        }

        public OutputWriter(Writer writer) {
            this.writer = new PrintWriter(writer);
        }

        public void println(Object... objects) {
            for (int i = 0; i < objects.length; i++) {
                if (i != 0) {
                    writer.print(' ');
                }
                writer.print(objects[i]);
            }
            writer.print('\n');
        }

        public void close() {
            writer.close();
        }

    }
}



Measured memory_bytes: 28116