#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
int segment[131072];
const int maxi = 1000000000;
int graph[50000][5][15][5];
void add(int pos, int a) {
pos += 65536;
segment[pos] = a;
pos /= 2;
while (pos > 0) {
if (segment[2*pos + 1] == -1 || segment[2*pos] == -1) {
segment[pos] = -1;
} else {
segment[pos] = segment[2*pos + 1] + segment[2*pos];
}
pos /= 2;
}
}
int find(int a, int b) {
a += 65536; b += 65536 - 1;
int val = 0;
while (a <= b) {
if (a % 2 == 1) {
if (segment[a] == -1) {
val = -1; break;
}
val += segment[a++];
}
if (b % 2 == 0) {
if (segment[b] == -1) {
val = -1; break;
}
val += segment[b--];
}
a /= 2; b /= 2;
}
if (val == 0) {
return -1;
}
return val;
}
int main() {
int k, n, m, o, d1, d2, t; cin >> k >> n >> m >> o;
if (k == 1) {
for (int i=0;i<131072;i++) {
segment[i] = -1;
}
for (int i=0;i<m;i++) {
cin >> d1 >> d2 >> t;
add(d1, t);
}
for (int i=0;i<o;i++) {
cin >> d1 >> d2;
cout << find(d1, d2) << '\n';
}
return 0;
}
int asdf = (n + k - 1) / k;
for (int i=0;i<50000;i++) {
for (int j=0;j<k;j++) {
for (int x=0;x<15;x++) {
for (int y=0;y<k;y++) {
graph[i][j][x][y] = maxi;
}
}
}
}
for (int i=0;i<m;i++) {
cin >> d1 >> d2 >> t;
graph[d1/k][d1%k][0][d2%k] = t;
}
int add = 1;
for (int i=1;i<15;i++) {
for (int j=0;j<asdf;j++) {
for (int x=0;x<k;x++) {
for (int y=0;y<k;y++) {
for (int z=0;z<k;z++) {
graph[j][x][i][y] = min(graph[j][x][i][y], graph[j][x][i-1][z] + graph[j + add][z][i-1][y]);
if (graph[j][x][i][y] > maxi) {
graph[j][x][i][y] = maxi;
}
}
}
}
}
add *= 2;
}
int ans[5], newans[5], pow2, pow2val, diff, amodk, adivk, bmodk, bdivk;
for (int i=0;i<o;i++) {
cin >> d1 >> d2;
amodk = d1 % k; adivk = d1 / k;
bmodk = d2 % k; bdivk = d2 / k;
pow2val = 16384; pow2 = 14;
diff = bdivk - adivk;
if (diff <= 0) {
cout << -1 << '\n'; continue;
}
while (true) {
if (diff < pow2val) {
pow2val /= 2;
pow2 -= 1;
continue;
}
diff -= pow2val;
//cout << pow2 << '\n';
for (int j=0;j<k;j++) {
ans[j] = graph[adivk][amodk][pow2][j];
}
adivk += pow2val;
pow2val /= 2;
pow2 -= 1;
break;
}
//cout << ans[0] << ' ' << ans[2] << ' ' << adivk << ' ' << pow2 << '\n';
while (diff > 0) {
if (diff < pow2val) {
pow2val /= 2;
pow2 -= 1;
continue;
}
diff -= pow2val;
for (int j=0;j<k;j++) {
newans[j] = maxi;
for (int x=0; x<k;x++) {
if (graph[adivk][x][pow2][j] < maxi && ans[x] < maxi) {
newans[j] = min(newans[j], graph[adivk][x][pow2][j] + ans[x]);
}
}
}
for (int j=0;j<k;j++) {
ans[j] = newans[j];
}
adivk += pow2val;
pow2val /= 2;
pow2 -= 1;
}
if (ans[bmodk] == maxi) {
cout << -1 << '\n'; continue;
}
cout << ans[bmodk] << '\n';
}
}
