#include <bits/stdc++.h>
using namespace std;
#define task ""
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i, a, b) for (int i = (b), _a = (a); i >= _a; --i)
template <typename T1, typename T2> bool minimize(T1 &a, T2 b) {
if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b) {
if (a < b) {a = b; return true;} return false;
}
const int dx[] = {-1, 0, 0, +1};
const int dy[] = {0, -1, +1, 0};
const int INF = 1e9 + 7;
const int MAX = 50000;
int k, n, m, q;
int dp[MAX][16][5];
#define ID(i, j, t) (((i) / k + (1 << (j))) * k + (t))
int main() {
ios_base::sync_with_stdio(false); cin.tie(nullptr);
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
cin >> k >> n >> m >> q;
for (int j = 0; j <= 15; ++j) {
for (int i = 0; i < n; ++i)
for (int t = 0; t < 5; ++t)
dp[i][j][t] = INF;
}
while (m--) {
int a, b, t; cin >> a >> b >> t;
dp[a][0][b % k] = t;
}
for (int j = 1; j <= 15; ++j) {
for (int i = 0; i < n; ++i) {
for (int m = 0; m < k; ++m) {
for (int t = 0; t < k; ++t) {
if (ID(i, j, t) >= n) continue;
if (dp[i][j - 1][m] >= INF) continue;
if (dp[ID(i, j - 1, m)][j - 1][t] >= INF) continue;
minimize(dp[i][j][t], dp[i][j - 1][m] + dp[ID(i, j - 1, m)][j - 1][t]);
}
}
}
}
while (q--) {
int a, b; cin >> a >> b;
vector<int> curDist(5, INF), nextDist(5, INF);
curDist[a % k] = 0;
int u = a / k, v = b / k;
for (int j = 15; j >= 0; --j) {
if (u + (1 << j) <= v) {
for (int m = 0; m < k; ++m) {
for (int t = 0; t < k; ++t) {
minimize(nextDist[t], curDist[m] + dp[u * k + m][j][t]);
}
}
curDist = nextDist; u += 1 << j;
nextDist.assign(k, INF);
}
}
int res = curDist[b % k];
if (res == INF) res = -1;
cout << res << '\n';
}
return 0;
}
