#include <bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define pb push_back
#define all(a) a.begin(), a.end()
#define inc(i, a, b) for (int i = a; i <= b; i++)
#define dec(i, a, b) for (int i = a; i >= b; i--)
typedef long long ll;
typedef pair<int, int> ii;
void print() { cerr << '\n'; }
template <typename T, typename... Args>
void print(const T &a, const Args &...args) { cerr << a << ' ', print(args...); }
int k, n, m, t;
int dp[50000][17][5][5], res[5][5], tmp[5][5];
#define mem(a, val) inc(i, 0, 4) inc(j, 0, 4) a[i][j] = val;
signed main()
{
cin.tie(0)->sync_with_stdio(0);
cin >> k >> n >> m >> t;
memset(dp, 0x3f, sizeof dp);
while (m--)
{
int a, b, t;
cin >> a >> b >> t;
dp[a / k][0][a % k][b % k] = t;
}
auto combine = [&](int target[5][5], int a[5][5], int b[5][5])
{
inc(i, 0, k -1) inc(j, 0, k - 1) inc(K, 0, k - 1)
target[i][j] = min(target[i][j], a[i][K] + b[K][j]);
};
for (int j = 1; j < 17; j++)
for (int i = 0; i + (1 << j) < (n + k - 1) / k; i++)
combine(dp[i][j], dp[i][j - 1], dp[i + (1 << (j - 1))][j - 1]);
while (t--)
{
int a, b;
cin >> a >> b;
mem(res, 1e9);
inc(i, 0, 4) res[i][i] = 0;
int cur = a / k;
dec(i, 16, 0)
{
if (cur + (1 << i) <= b / k)
{
mem(tmp, 1e9);
combine(tmp, res, dp[cur][i]);
mem(res, tmp[i][j]);
cur += (1 << i);
}
}
a %= k, b %= k;
cout << (res[a][b] == 1e9 ? -1 : res[a][b]) << '\n';
}
return 0;
}
