import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.nio.charset.Charset;
import java.util.NoSuchElementException;
import java.io.OutputStream;
import java.nio.CharBuffer;
import java.io.IOException;
import java.nio.charset.CharsetDecoder;
import java.lang.reflect.Field;
import java.nio.charset.StandardCharsets;
import java.io.UncheckedIOException;
import java.util.Objects;
import java.util.List;
import java.io.Writer;
import java.io.InputStream;

/**
 * Built using CHelper reloaded plug-in
 * Actual solution is at the top
 *
 * @author mikit
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        LightScanner2 in = new LightScanner2(inputStream);
        LightWriter2 out = new LightWriter2(outputStream);
        No1207X solver = new No1207X();
        solver.solve(1, in, out);
        out.close();
    }

    static class No1207X {
        private static final int MOD = (int) 1e9 + 7;

        public void solve(int testNumber, LightScanner2 in, LightWriter2 out) {
            ModMath mod = new ModMath(MOD);
            int n = in.ints(), m = in.ints(), b = in.ints();
            No1207X.Node[] nodes = new No1207X.Node[n];
            for (int i = 0; i < n; i++) nodes[i] = new No1207X.Node();
            IntUnionFind uf = new IntUnionFind(n);
            for (int i = 0; i < m; i++) {
                int x = in.ints() - 1, y = in.ints() - 1, z = in.ints();
                if (uf.find(x) == uf.find(y)) continue;
                uf.union(x, y);
                nodes[x].edges.add(new No1207X.Edge(nodes[y], mod.pow(b, z)));
                nodes[y].edges.add(new No1207X.Edge(nodes[x], mod.pow(b, z)));
            }
            nodes[0].dfs(null);
            long ans = 0;
            for (No1207X.Node node : nodes) {
                for (No1207X.Edge edge : node.edges) {
                    if (edge.size == -1) continue;
                    //System.out.println(edge.size + " : " + edge.cost);
                    long p = edge.size * (long) (n - edge.size) % MOD;
                    p *= edge.cost;
                    ans += p % MOD;
                }
                ans %= MOD;
            }
            out.ans(ans).ln();
        }

        private static class Node {
            List<No1207X.Edge> edges = new ArrayList<>();
            int size = -1;

            void dfs(No1207X.Node from) {
                size = 1;
                for (No1207X.Edge edge : edges) {
                    if (edge.dest == from) continue;
                    edge.dest.dfs(this);
                    edge.size = edge.dest.size;
                    size += edge.dest.size;
                }
            }

        }

        private static class Edge {
            No1207X.Node dest;
            long cost;
            int size = -1;

            Edge(No1207X.Node dest, long cost) {
                this.dest = dest;
                this.cost = cost;
            }

        }

    }

    static class LightScanner2 extends LightScannerAdapter {
        private static final int BUF_SIZE = 32 * 1024;
        private final InputStream stream;
        private final byte[] buf = new byte[BUF_SIZE];
        private int ptr;
        private int len;

        public LightScanner2(InputStream stream) {
            this.stream = stream;
        }

        private int read() {
            if (ptr < len) return buf[ptr++];
            try {
                ptr = 0;
                len = stream.read(buf);
            } catch (IOException ex) {
                throw new UncheckedIOException(ex);
            }
            if (len == -1) return -1;
            return buf[ptr++];
        }

        private void skip() {
            int b;
            while (isTokenSeparator(b = read()) && b != -1) ;
            if (b == -1) throw new NoSuchElementException("EOF");
            ptr--;
        }

        public int ints() {
            long x = longs();
            if (x < Integer.MIN_VALUE || Integer.MAX_VALUE < x) throw new NumberFormatException("Overflow");
            return (int) x;
        }

        public long longs() {
            skip();
            int b = read();
            boolean negate;
            if (b == '-') {
                negate = true;
                b = read();
            } else negate = false;
            long x = 0;
            for (; !isTokenSeparator(b); b = read()) {
                if ('0' <= b && b <= '9') x = x * 10 + b - '0';
                else throw new NumberFormatException("Unexpected character '" + b + "'");
            }
            return negate ? -x : x;
        }

        public void close() {
            try {
                stream.close();
            } catch (IOException e) {
                throw new UncheckedIOException(e);
            }
        }

        private static boolean isTokenSeparator(int b) {
            return b < 33 || 126 < b;
        }

    }

    static interface Verified {
    }

    static class ModMath {
        private static final int DEFAULT_MOD = 1_000_000_007;
        private final long mod;

        public ModMath(long mod, boolean unsafe) {
        /*if (!unsafe && !IntMath.isPrime(mod)) {
            throw new RuntimeException("This class is designed for primes!");
        }*/
            this.mod = mod;
        }

        public ModMath(long mod) {
            this(mod, false);
        }

        public ModMath() {
            this(DEFAULT_MOD, true);
        }

        public long mod(long x) {
            x %= mod;
            return x < 0 ? x + mod : x;
        }

        public long inv(long x) {
            //return pow(x, mod - 2);
            return mod(LongEuclidSolver.solve(x, mod).x);
        }

        public long pow(long x, long y) {
            y %= (mod - 1);
            if (y < 0) {
                return pow(inv(x), -y);
            } else if (y == 0) {
                return 1;
            } else if (y % 2 == 0) {
                long z = pow(x, y / 2);
                return (z * z) % mod;
            } else {
                return (x % mod) * pow(x, y - 1) % mod;
            }
        }

    }

    static class Vec3i implements Comparable<Vec3i> {
        public int x;
        public int y;
        public int z;

        public Vec3i(int x, int y, int z) {
            this.x = x;
            this.y = y;
            this.z = z;
        }

        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;
            Vec3i vec3i = (Vec3i) o;
            return x == vec3i.x &&
                    y == vec3i.y &&
                    z == vec3i.z;
        }

        public int hashCode() {
            return Objects.hash(x, y, z);
        }

        public String toString() {
            return "(" + x + ", " + y + ", " + z + ")";
        }

        public int compareTo(Vec3i o) {
            if (x == o.x) {
                if (y == o.y) {
                    return Integer.compare(z, o.z);
                }
                return Integer.compare(y, o.z);
            }
            return Integer.compare(x, o.x);
        }

    }

    static class LongEuclidSolver {
        private LongEuclidSolver() {
        }

        public static Vec3l solve(long a, long b) {
            LongEuclidSolver.ReferenceLong p = new LongEuclidSolver.ReferenceLong(), q = new LongEuclidSolver.ReferenceLong();
            long d = solve(a, b, p, q);
            return new Vec3l(p.val, q.val, d);
        }

        private static long solve(long a, long b, LongEuclidSolver.ReferenceLong p, LongEuclidSolver.ReferenceLong q) {
            if (b == 0) {
                p.val = 1;
                q.val = 0;
                return a;
            } else {
                long d = solve(b, a % b, q, p);
                q.val -= (a / b) * p.val;
                return d;
            }
        }

        private static class ReferenceLong {
            private long val;

        }

    }

    static class LightWriter2 implements AutoCloseable {
        private static final int BUF_SIZE = 32 * 1024;
        private static final int BUF_THRESHOLD = 1024;
        private final OutputStream out;
        private final byte[] buf = new byte[BUF_SIZE];
        private int ptr;
        private final Field fastStringAccess;
        private boolean autoflush = false;
        private boolean breaked = true;

        public LightWriter2(OutputStream out) {
            this.out = out;
            Field f;
            try {
                f = String.class.getDeclaredField("value");
                f.setAccessible(true);
                if (f.getType() != byte[].class) f = null;
            } catch (ReflectiveOperationException ignored) {
                f = null;
            }
            this.fastStringAccess = f;
        }

        public LightWriter2(Writer out) {
            this.out = new LightWriter2.WriterOutputStream(out);
            this.fastStringAccess = null;
        }

        private void allocate(int n) {
            if (ptr + n <= BUF_SIZE) return;
            try {
                out.write(buf, 0, ptr);
                ptr = 0;
            } catch (IOException ex) {
                throw new UncheckedIOException(ex);
            }
            if (BUF_SIZE < n) throw new IllegalArgumentException("Internal buffer exceeded");
        }

        public void close() {
            try {
                out.write(buf, 0, ptr);
                ptr = 0;
                out.flush();
                out.close();
            } catch (IOException ex) {
                throw new UncheckedIOException(ex);
            }
        }

        public LightWriter2 print(char c) {
            allocate(1);
            buf[ptr++] = (byte) c;
            breaked = false;
            return this;
        }

        public LightWriter2 print(String s) {
            byte[] bytes;
            if (this.fastStringAccess == null) bytes = s.getBytes();
            else {
                try {
                    bytes = (byte[]) fastStringAccess.get(s);
                } catch (IllegalAccessException ignored) {
                    bytes = s.getBytes();
                }
            }
            int n = bytes.length;
            if (n <= BUF_THRESHOLD) {
                allocate(n);
                System.arraycopy(bytes, 0, buf, ptr, n);
                ptr += n;
                return this;
            }
            try {
                out.write(buf, 0, ptr);
                ptr = 0;
                out.write(bytes);
                out.flush();
            } catch (IOException ex) {
                throw new UncheckedIOException(ex);
            }
            return this;
        }

        public LightWriter2 ans(long l) {
            if (!breaked) {
                print(' ');
            }
            if (l == 0) return print('0');
            if (l < 0) {
                print('-');
                l = -l;
            }
            int n = 0;
            long t = l;
            while (t > 0) {
                t /= 10;
                n++;
            }
            allocate(n);
            for (int i = 1; i <= n; i++) {
                buf[ptr + n - i] = (byte) (l % 10 + '0');
                l /= 10;
            }
            ptr += n;
            return this;
        }

        public LightWriter2 ln() {
            print(System.lineSeparator());
            breaked = true;
            if (autoflush) {
                try {
                    out.flush();
                } catch (IOException ex) {
                    throw new UncheckedIOException(ex);
                }
            }
            return this;
        }

        private static class WriterOutputStream extends OutputStream {
            final Writer writer;
            final CharsetDecoder decoder;

            WriterOutputStream(Writer writer) {
                this.writer = writer;
                this.decoder = StandardCharsets.UTF_8.newDecoder();
            }

            public void write(int b) throws IOException {
                writer.write(b);
            }

            public void write(byte[] b) throws IOException {
                writer.write(decoder.decode(ByteBuffer.wrap(b)).array());
            }

            public void write(byte[] b, int off, int len) throws IOException {
                writer.write(decoder.decode(ByteBuffer.wrap(b, off, len)).array());
            }

            public void flush() throws IOException {
                writer.flush();
            }

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

        }

    }

    static final class IntUnionFind {
        private int groups;
        private final int[] nodes;
        private final int[] rank;

        public IntUnionFind(int n) {
            groups = n;
            nodes = new int[n];
            Arrays.fill(nodes, -1);
            rank = new int[n];
        }

        public int find(int i) {
            int ans = nodes[i];
            if (ans < 0) {
                return i;
            } else {
                return nodes[i] = find(ans);
            }
        }

        public boolean union(int x, int y) {
            x = find(x);
            y = find(y);
            if (x == y) {
                return false;
            } else if (rank[x] < rank[y]) {
                nodes[y] += nodes[x];
                nodes[x] = y;
            } else if (rank[x] == rank[y]) {
                rank[x]++;
                nodes[x] += nodes[y];
                nodes[y] = x;
            } else {
                nodes[x] += nodes[y];
                nodes[y] = x;
            }
            groups--;
            return true;
        }

    }

    static class Vec3l implements Comparable<Vec3l> {
        public long x;
        public long y;
        public long z;

        public Vec3l(long x, long y, long z) {
            this.x = x;
            this.y = y;
            this.z = z;
        }

        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;
            Vec3i vec3i = (Vec3i) o;
            return x == vec3i.x &&
                    y == vec3i.y &&
                    z == vec3i.z;
        }

        public int hashCode() {
            return Objects.hash(x, y, z);
        }

        public String toString() {
            return "(" + x + ", " + y + ", " + z + ")";
        }

        public int compareTo(Vec3l o) {
            if (x == o.x) {
                if (y == o.y) {
                    return Long.compare(z, o.z);
                }
                return Long.compare(y, o.z);
            }
            return Long.compare(x, o.x);
        }

    }

    static abstract class LightScannerAdapter implements AutoCloseable {
        public abstract void close();

    }
}