cube-185

#include <bits/stdc++.h>
using namespace std;
typedef long long int lli;
typedef pair<int,int> pii;

int main(){
    int n,m,t,x,y;
    scanf("%d %d %d",&n,&m,&t);
    vector<pii> adj[n+3];
    scanf("%d %d",&x,&y);
    for(int i=0;i<m;++i){
        int u,v,w;
        scanf("%d %d %d",&u,&v,&w);
        adj[u].push_back({v,w});
    }
    priority_queue<pair<lli,pii>,vector<pair<lli,pii>>,greater<pair<lli,pii>>> pq;
    pq.push({0,{x,1}});
    vector<vector<bool>> visited(n+3,vector<bool>(t+1,false));
    while(!pq.empty()){
        lli d = pq.top().first;
        int u = pq.top().second.first;
        int k = pq.top().second.second;
        pq.pop();
        if(k == 0 && u == y){
            printf("%lld",d);
            return 0;
        }
        if(visited[u][k]){
            continue;
        }
        visited[u][k] = true;
        for(auto v : adj[u]){
            if(!visited[v.first][(k+1)%t]){
                pq.push({d + v.second,{v.first,(k+1)%t}});
            }
        }
    }
    printf("-1");
    return 0;
}