import java.util.*;
import java.util.Map.Entry;

import javax.swing.text.Segment;
import javax.xml.ws.WebEndpoint;

import java.io.*;
import java.lang.reflect.Array;
import java.math.BigInteger;

import static java.lang.Math.*;
import static java.util.Arrays.*;
import static java.util.Collections.*;
 
public class Main //implements Runnable
{
//    static int dx[]={-1,0,1,0};
//    static int dy[]={0,-1,0,1};

    public static void main(String[] args)   throws Exception, IOException{        
        long mod=1000000007;
        Reader sc = new Reader(System.in);
        PrintWriter out=new PrintWriter(System.out);
        
        int n=sc.nextInt();
        int m=sc.nextInt();
        int l=sc.nextInt();
        long d[][]=new long[n][n];
        long w[][]=new long[n][n];
        long inf=1L<<40;
        for (int i = 0; i < d.length; i++) {
			fill(d[i],inf);
			fill(w[i],inf);
		}
        for (int i = 0; i < m; i++) {
			int a=sc.nextInt()-1;
			int b=sc.nextInt()-1;
			int c=sc.nextInt();
			d[a][b]=d[b][a]=c;
		}
        int q=sc.nextInt();
        
        for (int i = 0; i < n; i++)
            for (int j = 0; j < n; j++)
              for (int k = 0; k < n; k++)
            	  if(d[j][i] + d[i][k]<d[j][k])
                      d[j][k] = d[j][i] + d[i][k];

        for (int i = 0; i < d.length; i++) {
        	for (int j = i+1; j < w.length; j++) {
				if(d[i][j]<=l)w[i][j]=w[j][i]=1;
			}
		}

        for (int i = 0; i < n; i++)
            for (int j = 0; j < n; j++)
              for (int k = 0; k < n; k++)
            	  if(w[j][i] + w[i][k]<w[j][k])
                      w[j][k] = w[j][i] + w[i][k];
        
        
        for (int i = 0; i < q; i++) {
			int s=sc.nextInt()-1;
			int t=sc.nextInt()-1;	        
	        out.println(w[s][t]==inf?-1:(w[s][t]-1));
		}
        out.println();
     	out.flush();
    }
    
    static void ret(String ans) {
    	System.out.println(ans);
    	System.exit(0);
    }
    
    static boolean validpos(int x,int y,int r, int c){
        return x<r && 0<=x && y<c && 0<=y;
    }

    static void db(Object... os){
        System.err.println(Arrays.deepToString(os));
    }
}


class P {
	int x, y, d;
	P(int  x, int y, int d) {
	  this.x=x;
	  this.y=y;
	  this.d=d;
	}
}

//class P implements Comparable<P>{
//    int a,b;
//    P(int a, int b) {
//    	this.b=b;
//    	this.a=a;
//    }
//
//    public int compareTo(P p){
//        return p.a-a;//des
//    }
//}

class Reader
{ 
    private BufferedReader x;
    private StringTokenizer st;
    
    public Reader(InputStream in)
    {
        x = new BufferedReader(new InputStreamReader(in));
        st = null;
    }
    public String nextString() throws IOException
    {
        while( st==null || !st.hasMoreTokens() )
            st = new StringTokenizer(x.readLine());
        return st.nextToken();
    }
    public int nextInt() throws IOException
    {
        return Integer.parseInt(nextString());
    }
    public int[] nextIntArray(int size) throws IOException{
        int r[] = new int[size];
        for (int i = 0; i < size; i++) {
            r[i] = this.nextInt(); 
        }
        return r;
    }
    public long[] nextLongArray(int size) throws IOException{
        long r[] = new long[size];
        for (int i = 0; i < size; i++) {
            r[i] = this.nextLong(); 
        }
        return r;
    }
    public char[] getCharSet() throws IOException{
        return this.nextString().toCharArray();
    }    
    public long nextLong() throws IOException
    {
        return Long.parseLong(nextString());
    }
    public double nextDouble() throws IOException
    {
        return Double.parseDouble(nextString());
    }
}


Measured memory_bytes: 46956