import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.*;

public class Main {
	static final long MOD=1000000007;//998244353;
	public static void main(String[] args) {
		PrintWriter out = new PrintWriter(System.out);
		InputReader sc=new InputReader(System.in);
		int N=sc.nextInt();
		int M=sc.nextInt();
		int L=sc.nextInt();
		graph G=new graph(N);
		for (int i = 0; i < M; i++) {
			int a=sc.nextInt()-1;
			int b=sc.nextInt()-1;
			int c=sc.nextInt();
			if (c>L) {
				continue;
			}
			G.addEdge(a, b, c);
			G.addEdge(b, a, c);
		}
		long[][] ans=new long[N][N];
		int Q=sc.nextInt();
		for (int i = 0; i < N; i++) {
			ans[i]=G.dijkstra(i, L);
		}
		for (int i = 0; i < Q; i++) {
			int a=sc.nextInt()-1;
			int b=sc.nextInt()-1;
			if (ans[a][b]==Long.MAX_VALUE/2) {
				ans[a][b]=-1;
			}
			out.println(ans[a][b]);
		}
		out.flush();
   	}
	static class Edge implements Comparable<Edge>{
		int to;
		long v;
		public Edge(int to,long v) {
			this.to=to;
			this.v=v;
		}
		@Override
    	public boolean equals(Object obj) {
    		if(obj instanceof Edge) {
    			Edge other = (Edge) obj;
    			return other.to==this.to && other.v==this.v;
    		}
    		return false;
    	}//同値の定義
    	@Override
    	public int hashCode() {
    		return Objects.hash(this.to,this.v);
    	}
    	@Override
		  public int compareTo( Edge p2 ){
			 if (this.v>p2.v) {
				return 1;
			}
			 else if (this.v<p2.v) {
				return -1;
			}
			 else {
				if (this.to<p2.to) {
					return 1;
				}else if(this.to>p2.to){
					return -1;
				}else {
					return 0;
				}
			}
		  }
	} 
	static class graph{
		ArrayList<Edge>[] list;
		int size;
		long INF=Long.MAX_VALUE/2;
		int[] color;
		@SuppressWarnings("unchecked")
		public graph(int n) {
			size = n;
			list = new ArrayList[n];
			color =new int[n];
			for(int i=0;i<n;i++){
				list[i] = new ArrayList<Edge>();
			}
		}
		void addEdge(int from,int to,long w) {
			list[from].add(new Edge(to,w));
		}
		long[] dijkstra(int s,int X){
			Edge[] dp=new Edge[size];//残量,補給回数
			for (int i = 0; i < dp.length; i++) {
				dp[i]=new Edge(-899, INF);
			}
	        long[] L = new long[size];
	        for(int i=0;i<size;i++){
	            L[i] = -1;
	        }
	        dp[s]=new Edge(X, 0);
	        for (int i = 0; i < size; i++) {
	        	Edge max=new Edge(0, INF);
	        	int index=-1;
				for (int j = 0; j < size; j++) {
					if (dp[j].compareTo(max)<=0&&L[j]==-1) {
						index=j;
						max=dp[j];
					}
				}
				if (index==-1) {
					continue;
				}
				L[index]=max.v;
				for (Edge D: list[index]) {
					Edge p=null;
					if (max.to-D.v<0) {
						p=new Edge(X-(int)D.v, max.v+1);
					}else {
						p=new Edge(max.to-(int)D.v, max.v);
					}
					if (p.compareTo(dp[D.to])<=0) {
						dp[D.to]=p;
					}
				}
			}
	        return L;
	    }
	}
		static class InputReader { 
		private InputStream in;
		private byte[] buffer = new byte[1024];
		private int curbuf;
		private int lenbuf;
		public InputReader(InputStream in) {
			this.in = in;
			this.curbuf = this.lenbuf = 0;
		}
 
		public boolean hasNextByte() {
			if (curbuf >= lenbuf) {
				curbuf = 0;
				try {
					lenbuf = in.read(buffer);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (lenbuf <= 0)
					return false;
			}
			return true;
		}
 
		private int readByte() {
			if (hasNextByte())
				return buffer[curbuf++];
			else
				return -1;
		}
 
		private boolean isSpaceChar(int c) {
			return !(c >= 33 && c <= 126);
		}
 
		private void skip() {
			while (hasNextByte() && isSpaceChar(buffer[curbuf]))
				curbuf++;
		}
 
		public boolean hasNext() {
			skip();
			return hasNextByte();
		}
 
		public String next() {
			if (!hasNext())
				throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int b = readByte();
			while (!isSpaceChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		}
 
		public int nextInt() {
			if (!hasNext())
				throw new NoSuchElementException();
			int c = readByte();
			while (isSpaceChar(c))
				c = readByte();
			boolean minus = false;
			if (c == '-') {
				minus = true;
				c = readByte();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res = res * 10 + c - '0';
				c = readByte();
			} while (!isSpaceChar(c));
			return (minus) ? -res : res;
		}
 
		public long nextLong() {
			if (!hasNext())
				throw new NoSuchElementException();
			int c = readByte();
			while (isSpaceChar(c))
				c = readByte();
			boolean minus = false;
			if (c == '-') {
				minus = true;
				c = readByte();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res = res * 10 + c - '0';
				c = readByte();
			} while (!isSpaceChar(c));
			return (minus) ? -res : res;
		}
 
		public double nextDouble() {
			return Double.parseDouble(next());
		}
 
		public int[] nextIntArray(int n) {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}
 
		public long[] nextLongArray(int n) {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextLong();
			return a;
		}
 
		public char[][] nextCharMap(int n, int m) {
			char[][] map = new char[n][m];
			for (int i = 0; i < n; i++)
				map[i] = next().toCharArray();
			return map;
		}
	}
	}

Measured memory_bytes: 59240