#include <bits/stdc++.h>
using namespace std;

int mod = 1000000007;

int main() {
    int N,M,K;
    cin >> N >> M >> K;
    vector<vector<pair<int,int>>> road(N);
    for(int i = 0; i < M; i++) {
        int X,Y,Z;
        cin >> X >> Y >> Z;
        X--;
        Y--;
        road[X].push_back({Y,Z});
        road[Y].push_back({X,Z});
    }
    vector<vector<int>> dist(N,vector<int>(2,-mod));
    long long tmp = 1,tmp2 = 1;
    bool flag = true;
    for(int i = 0; i < N; i++) {
        if(dist[i][0] == -mod && dist[i][1] == -mod) {
            if(road[i].size() == 0) {
                tmp *= K;
                tmp2 *= K-1;
                tmp %= mod;
                tmp2 %= mod;
            }
            dist[i][0] = 0;
            vector<int> dist2;
            queue<pair<int,int>> que;
            que.push({i,0});
            while (!que.empty()) {
                pair<int,int> x = que.front();
                que.pop();
                dist2.push_back(x.first);
                for(int j = 0; j < road[x.first].size(); j++) {
                    pair<int,int> nx = {road[x.first][j].first,x.second^1};
                    if(dist[nx.first][nx.second] == -mod) {
                        dist[nx.first][nx.second] = road[x.first][j].second-dist[x.first][x.second];
                        que.push(nx);
                    }
                    else if(dist[nx.first][nx.second] != road[x.first][j].second-dist[x.first][x.second]){
                        flag = false;
                    }
                }
            }
            int gmi = mod,gmx = -mod,kmi = mod,kmx = -mod;
            int res = -mod;
            for(int j = 0; j < dist2.size(); j++) {
                if(dist[dist2[j]][0] != -mod) {
                    gmi = min(gmi,dist[dist2[j]][0]);
                    gmx = max(gmx,dist[dist2[j]][0]);
                }
                if(dist[dist2[j]][1] != -mod) {
                    kmi = min(kmi,dist[dist2[j]][1]);
                    kmx = max(kmx,dist[dist2[j]][1]);
                }
                if(dist[dist2[j]][0] != -mod && dist[dist2[j]][1] != -mod) {
                    int a = abs(dist[dist2[j]][0]-dist[dist2[j]][1]);
                    if(a%2 == 1) {
                        flag = false;
                    }
                    if(res == -mod) {
                        res = a/2;
                    }
                    else if(res != a/2) {
                        flag = false;
                    }
                }
            }
            if(res != -mod) {
                if(res >= 1 && res <= K && gmi+res >= 1 && gmx+res <= K && kmi-res >= 1 && kmx-res <= K) {
                    if(gmx+res == K || kmx-res == K) {
                        tmp2 = 0;
                    }
                }
                else {
                    flag = false;
                }
            }
            else {
                int mi = 0,mx = 0;
                mi = max(1,1-gmi);
                mx = min(K,K-gmx);
                mi = max(mi,kmx-K);
                mx = min(mx,kmi-1);
                if(mi > mx) {
                    flag = false;
                }
                tmp *= mx-mi+1;
                tmp %= mod;
                tmp2 *= mx-mi;
                tmp2 %= mod;
            }
        }
    }
    if(!flag) {
        cout << 0 << endl;
        return 0;
    }
    cout << (tmp+mod-tmp2)%mod << endl;
}