This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
//Then
#include <bits/stdc++.h>
#define pb push_back
#define fi first
#define se second
#define faster ios_base::sync_with_stdio(0); cin.tie(0);
#define int long long
using namespace std;
using ll = long long;
using ld = long double;
using pii = pair <int, int>;
mt19937_64 Rand(chrono::steady_clock::now().time_since_epoch().count());
const int maxN = 80 + 1;
//const int Mod = 1e9 + 7;
const ll inf = 0x3f3f3f3f3f3f3f3f;
int n, k, q, m;
int c[maxN][maxN];
struct TEdge{
    int u, i, w;
};
struct TPQ{
    int lab, u, i;
    bool operator < (const TPQ &other) const{
        return lab > other.lab;
    }
};
vector <TEdge> adj[maxN][maxN];
ll d[maxN][maxN][maxN];
void Dijkstra(int s){
    memset(d[s], 0x3f, sizeof(d[s]));
    priority_queue <TPQ> PQ;
    d[s][s][0] = 0;
    PQ.push({0, s, 0});
    while (!PQ.empty()){
        auto r = PQ.top(); PQ.pop();
        if (d[s][r.u][r.i] != r.lab) continue;
        for (auto i: adj[r.u][r.i]){
            if (d[s][i.u][i.i] > d[s][r.u][r.i] + i.w){
                d[s][i.u][i.i] = d[s][r.u][r.i] + i.w;
                PQ.push({d[s][i.u][i.i], i.u, i.i});
            }
        }
    }
    for (int i = 1; i <= n; ++i){
        for (int j = 1; j <= n; ++j){
            d[s][i][j] = min(d[s][i][j], d[s][i][j - 1]);
        }
    }
}
void Init(){
    cin >> n >> m;
    memset(c, 0x3f, sizeof(c));
    for(int i = 1; i <= m; ++i){
        int u, v, w;
        cin >> u >> v >> w;
        c[u][v] = min(c[u][v], w);
    }
    cin >> k >> q;
    k = min(k, n);
    for (int i = 1; i <= n; ++i){
        for (int j = 1; j <= n; ++j){
            if (c[i][j] == inf) continue;
            for (int l = 0; l < n; ++l){
                adj[i][l].pb({j, l + 1, c[i][j]});
            }
        }
    }
    for (int i = 1; i <= n; ++i){
        Dijkstra(i);
    }
    while (q--){
        int u, v;
        cin >> u >> v;
        cout << (d[u][v][k] == inf ? -1 : d[u][v][k]) << "\n";
    }
}
#define debug
#define taskname "test"
signed main(){
    faster
    if (fopen(taskname".inp", "r")){
        freopen(taskname".inp", "r", stdin);
        freopen(taskname".out", "w", stdout);
    }
    int tt = 1;
    //cin >> tt;
    while (tt--){
        Init();
    }
    if (fopen("timeout.txt", "r")){
        ofstream timeout("timeout.txt");
        timeout << signed(double(clock()) / CLOCKS_PER_SEC * 1000);
        timeout.close();
        #ifndef debug
        cerr << "Time elapsed: " << signed(double(clock()) / CLOCKS_PER_SEC * 1000) << "ms\n";
        #endif // debug
    }
}
Compilation message (stderr)
Main.cpp: In function 'int main()':
Main.cpp:88:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   88 |         freopen(taskname".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:89:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |         freopen(taskname".out", "w", stdout);
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