#include <bits/stdc++.h>

#define N 110 

#define M 1010 

#define K 30 

#define inf 0x3f3f3f3f 

using namespace std;

int g[N][N][K], p[N], c[N], a[N], b[N], w[N][N], f[N][N * N];

char *p1, *p2, buf[100000];

#define nc() (p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 100000, stdin), p1 == p2) ? EOF : *p1 ++ )

int rd() {

    int x = 0, f = 1;

    char c = nc();

    while (c < 48) {

        if (c == '-')

            f = -1;

        c = nc();

    }

    while (c > 47) {

        x = (((x << 2) + x) << 1) + (c ^ 48), c = nc();

    }

    return x * f;

}

int main() {

    int n = rd(), m = rd(), C = rd(), T = rd();

    memset(g, 0xef, sizeof g);

    for (int i = 1; i <= n; i ++ ) {

        p[i] = rd(), c[i] = rd();

        c[i] = min(c[i], C);

        g[i][i][0] = 0;

    }

    for (int i = 1; i <= m; i ++ ) {

        int x = rd(), y = rd(), z = rd();

        g[x][y][0] = z;

    }

    for (int k = 1; k <= 17; k ++ ) {

        for (int i = 1; i <= n; i ++ ) {

            for (int j = 1; j <= n; j ++ ) {

                for (int x = 1; x <= n; x ++ ) {

                    g[i][j][k] = max(g[i][j][k], g[i][x][k - 1] + g[x][j][k - 1]);

                }

            }

        }

    }

    for (int i = 1; i <= n; i ++ ) {

        for (int j = 1; j <= n; j ++ ) {

            a[j] = -inf;

        }

        a[i] = 0;

        for (int k = 0; k <= 17; k ++ ) {

            if((c[i] >> k) & 1) {

                for (int j = 1; j <= n; j ++ ) {

                    b[j] = -inf;

                    for (int x = 1; x <= n; x ++ ) {

                        b[j] = max(b[j], a[x] + g[x][j][k]);

                    }

                }

                for (int j = 1; j <= n; j ++ ) {

                    a[j] = b[j];

                }

            }

        }

        for (int j = 1; j <= n; j ++ ) {

            w[i][j] = a[j];

        }

    }

    for (int q = 0; q <= n * n; q ++ ) {

        for (int x = 1; x <= n; x ++ ) {

            if (q >= p[x]) {

                for (int y = 1; y <= n; y ++ ) {

                    f[x][q] = max(f[x][q], f[y][q - p[x]] + w[x][y]);

                }

            }

        }

    }

    while (T -- ) {

        int s = rd(), q = rd(), d = rd();

        int pl = lower_bound(f[s], f[s] + n * n + 1, d) - f[s];

        if (pl > q) {

            puts("-1");

        }

        else {

            printf("%d\n", q - pl);

        }

    }

    return 0;

}