#include <stdio.h>
#define input "amenzi.in"
#define output "amenzi.out"
#define nmax 151
#define tmax 3501
long n,m,p,k,i,j,a,b,c,v[nmax][nmax],timp,nod,cost,amenda[nmax][tmax],ajunge[tmax][nmax],max,intersectie;
long s[tmax][nmax],nv[nmax],tp[nmax][nmax];
int main()
{
	FILE *fin, *fout;
	fin=fopen(input,"r");
	fout=fopen(output,"w");
	fscanf(fin,"%ld %ld %ld %ld",&n,&m,&k,&p);
	for (i=1;i<=m;i++)
		{
		 fscanf(fin,"%ld %ld %ld",&a,&b,&c);
		 v[a][++nv[a]]=b;
		 v[b][++nv[b]]=a;
		 tp[a][nv[a]]=c;
		 tp[b][nv[b]]=c;
		}
	for (i=1;i<=k;i++)
		{
		 fscanf(fin,"%ld %ld %ld",&nod,&timp,&cost);
		 amenda[nod][timp]=cost;		 
		}
	
	ajunge[0][1]=1;
	for (timp=0;timp<tmax;timp++)
		for (i=1;i<=n;i++)
			{
			if (ajunge[timp][i]) ajunge[timp+1][i]=ajunge[timp][i];
			if (ajunge[timp][i]==1)
				for (k=1;k<=nv[i];k++) 
					ajunge[timp+tp[i][k]][v[i][k]]=1;
			}	
    
	for (timp=0;timp<tmax;timp++)
		for (i=1;i<=n;i++)
			if (ajunge[timp][i])
				{
				 max=0;
				 for (k=1;k<=nv[i];k++)
					 if (ajunge[timp-tp[i][k]][v[i][k]])
						 if (s[timp-tp[i][k]][v[i][k]]>max)
							 max=s[timp-tp[i][k]][v[i][k]];
                 s[timp][i]=max+amenda[i][timp];
				}

    for (i=1;i<=p;i++)
		{
		 fscanf(fin,"%ld %ld",&intersectie,&timp);
		 fprintf(fout,"%ld\n",s[timp][intersectie]);
		}
	fclose(fin);
	fclose(fout);
	return 0;	
}