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

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
 
    long long N,M,K; cin >> N >> M >> K;
    vector<vector<pair<int,long long>>> Graph(N);
    for(int i=0; i<M; i++){
        int u,v; cin >> u >> v;
        u--; v--;
        long long w; cin >> w;
        Graph.at(u).push_back({v,w%K});
        Graph.at(v).push_back({u,w%K});
    }   
    while(true){
        vector<long long> dist(N,-1);
        dist.at(0) = 0;
        long long loop = 0;
        auto dfs = [&](auto dfs,int pos) -> void {
            long long d = dist.at(pos);
            for(auto [to,w] : Graph.at(pos)){
                long long now = d+w;
                if(now >= K) now -= K;
                if(dist.at(to) == -1){
                    dist.at(to) = now;
                    dfs(dfs,to);
                    if(loop) return;
                }
                else if(dist.at(to) != now){
                    loop = abs(dist.at(to)-now);
                    return;
                }
            }
        };
        dfs(dfs,0);
        if(loop == 0){cout << dist.at(N-1) << "\n"; break;}
        K = gcd(K,loop);
        for(int i=0; i<N; i++) for(auto &[to,w] : Graph.at(i)) w %= K;
    }
}