Problem:
Score : 500 points

Problem Statement

There are N towns numbered 1 to N and M roads. The i-th road connects Town A_i and Town B_i bidirectionally and has a length of C_i.

Takahashi will travel between these towns by car, passing through these roads. The fuel tank of his car can contain at most L liters of fuel, and one liter of fuel is consumed for each unit distance traveled. When visiting a town while traveling, he can full the tank (or choose not to do so). Travel that results in the tank becoming empty halfway on the road cannot be done.

Process the following Q queries:

The tank is now full. Find the minimum number of times he needs to full his tank while traveling from Town s_i to Town t_i. If Town t_i is unreachable, print -1.

Constraints

All values in input are integers.

2 \leq N \leq 300

0 \leq M \leq \frac{N(N-1)}{2}

1 \leq L \leq 10^9

1 \leq A_i, B_i \leq N

A_i \neq B_i

\left(A_i, B_i\right) \neq \left(A_j, B_j\right) (if i \neq j)

\left(A_i, B_i\right) \neq \left(B_j, A_j\right) (if i \neq j)

1 \leq C_i \leq 10^9

1 \leq Q \leq N\left(N-1\right)

1 \leq s_i, t_i \leq N

s_i \neq t_i

\left(s_i, t_i\right) \neq \left(s_j, t_j\right) (if i \neq j)

Input

Input is given from Standard Input in the following format:

N M L
A_1 B_1 C_1
:
A_M B_M C_M
Q
s_1 t_1
:
s_Q t_Q

Output

Print Q lines.

The i-th line should contain the minimum number of times the tank needs to be fulled while traveling from Town s_i to Town t_i. If Town t_i is unreachable, the line should contain -1 instead.

Sample Input 1

3 2 5
1 2 3
2 3 3
2
3 2
1 3

Sample Output 1

0
1

To travel from Town 3 to Town 2, we can use the second road to reach Town 2 without fueling the tank on the way.

To travel from Town 1 to Town 3, we can first use the first road to get to Town 2, full the tank, and use the second road to reach Town 3.

Sample Input 2

4 0 1
1
2 1

Sample Output 2

-1

There may be no road at all.

Sample Input 3

5 4 4
1 2 2
2 3 2
3 4 3
4 5 2
20
2 1
3 1
4 1
5 1
1 2
3 2
4 2
5 2
1 3
2 3
4 3
5 3
1 4
2 4
3 4
5 4
1 5
2 5
3 5
4 5

Sample Output 3

0
0
1
2
0
0
1
2
0
0
0
1
1
1
0
0
2
2
1
0

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
import java.io.*;
import java.math.*;
public class Main {
	static boolean DEBUG;
	public static void main(String[] args) {
		DEBUG = args.length > 0 && args[0].equals("-DEBUG");
		Solver solver = new Solver();
		solver.solve();
		solver.exit();
	}

	static class FastScanner {
		private final InputStream in = System.in;
		private final byte[] buffer = new byte[1024];
		private int ptr = 0;
		private int buflen = 0;
		private boolean hasNextByte() {
			if(ptr < buflen) {
				return true;
			}else{
				ptr = 0;
				try {
					buflen = in.read(buffer);
				} catch (IOException e) {
					e.printStackTrace();
				}
				if(buflen <= 0) {
					return false;
				}
			}
			return true;
		}
		private int readByte() { if(hasNextByte()) return buffer[ptr++]; else return -1;}
		private boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
		private void skipUnprintable() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;}
		public boolean hasNext() { skipUnprintable(); return hasNextByte();}
		public String next() {
			if(!hasNext()) throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int b = readByte();
			while(isPrintableChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		}
		public long nextLong() {
			if(!hasNext()) throw new NoSuchElementException();
			long n = 0;
			boolean minus = false;
			int b = readByte();
			if(b == '-') {
				minus = true;
				b = readByte();
			}
			if(b < '0' || '9' < b) {
				throw new NumberFormatException();
			}
			while(true){
				if('0' <= b && b <= '9') {
					n *= 10;
					n += b - '0';
				}else if(b == -1 || !isPrintableChar(b)){
					return minus ? -n : n;
				}else{
					throw new NumberFormatException();
				}
				b = readByte();
			}
		}
	}

	static class Solver {
		FastScanner sc = new FastScanner();
		public Solver() { }

		String ns() { return sc.next(); }
		String[] ns(int n) {
			String a[] = new String[n];
			for(int i = 0; i < n; i ++) { a[i] = ns(); }
			return a;
		}
		String[][] ns(int n, int m) {
			String a[][] = new String[n][m];
			for(int i = 0; i < n; i ++) { a[i] = ns(m); }
			return a;
		}
		char[] nc(int n) {
			String str = ns();
			char a[] = new char[max(n, str.length())];
			for(int i = 0; i < str.length(); i ++) { a[i] = str.charAt(i); }
			return a;
		}
		char[][] nc(int n, int m) {
			char a[][] = new char[n][m];
			for(int i = 0; i < n; i ++) { a[i] = nc(m); }
			return a;
		}
		boolean[] nb(int n, char t) {
			char c[] = nc(-1);
			if(n < 0) n = c.length;
			boolean a[] = new boolean[n];
			for(int i = 0; i < n; i ++) { a[i] = c[i] == t; }
			return a;
		}
		boolean[][] nb(int n, int m, char t) {
			boolean a[][] = new boolean[n][m];
			for(int i = 0; i < n; i ++) { a[i] = nb(m, t); }
			return a;
		}
		int ni() { return (int)sc.nextLong(); }
		int[] ni(int n) {
			int a[] = new int[n];
			for(int i = 0; i < n; i ++) { a[i] = ni(); }
			return a;
		}
		int[][] ni(int n, int m) {
			int a[][] = new int[n][m];
			for(int i = 0; i < n; i ++) { a[i] = ni(m); }
			return a;
		}
		long nl() { return sc.nextLong(); }
		long[] nl(int n) {
			long a[] = new long[n];
			for(int i = 0; i < n; i ++) { a[i] = nl(); }
			return a;
		}
		long[][] nl(int n, int m) {
			long a[][] = new long[n][m];
			for(int i = 0; i < n; i ++) { a[i] = nl(m); }
			return a;
		}
		double nd() { return Double.parseDouble(sc.next()); }
		double[] nd(int n) {
			double a[] = new double[n];
			for(int i = 0; i < n; i ++) { a[i] = nd(); }
			return a;
		}
		double[][] nd(int n, int m) {
			double a[][] = new double[n][m];
			for(int i = 0; i < n; i ++) { a[i] = nd(m); }
			return a;
		}

		PrintWriter out = new PrintWriter(System.out);
		PrintWriter err = new PrintWriter(System.err);
		void prt() { out.print(""); }
		<T> void prt(T a) { out.print(a); }
		void prtln() { out.println(""); }
		<T> void prtln(T a) { out.println(a); }
		void prtln(int... a) {
			StringBuilder sb = new StringBuilder();
			for(int element : a){ sb.append(element+" "); }
			prtln(sb.toString().trim());
		}
		void prtln(long... a) {
			StringBuilder sb = new StringBuilder();
			for(long element : a){ sb.append(element+" "); }
			prtln(sb.toString().trim());
		}
		void prtln(double... a) {
			StringBuilder sb = new StringBuilder();
			for(double element : a){ sb.append(element+" "); }
			prtln(sb.toString().trim());
		}
		void prtln(String... a) {
			StringBuilder sb = new StringBuilder();
			for(String element : a){ sb.append(element+" "); }
			prtln(sb.toString().trim());
		}
		void prtln(char... a) {
			StringBuilder sb = new StringBuilder();
			for(char element : a){ sb.append(element); }
			prtln(sb.toString().trim());
		}
		void prtln(int[][] a) { for(int[] element : a){ prtln(element); } }
		void prtln(long[][] a) { for(long[] element : a){ prtln(element); } }
		void prtln(double[][] a) { for(double[] element : a){ prtln(element); } }
		void prtln(String[][] a) { for(String[] element : a){ prtln(element); } }
		void prtln(char[][] a) { for(char[] element : a){ prtln(element); } }
		String errconvert(int a) { return isINF(a) ? "_" : String.valueOf(a); }
		String errconvert(long a) { return isINF(a) ? "_" : String.valueOf(a); }
		void errprt(int a) { if(DEBUG) { err.print(errconvert(a)); } }
		void errprt(long a) { if(DEBUG) { err.print(errconvert(a)); } }
		void errprt() { if(DEBUG) { err.print(""); } }
		<T> void errprt(T a) { if(DEBUG) { err.print(a); } }
		void errprt(boolean a) { if(DEBUG) { errprt(a ? "#" : "."); } }
		void errprtln() { if(DEBUG) { err.println(""); } }
		void errprtln(int a) { if(DEBUG) { err.println(errconvert(a)); } }
		void errprtln(long a) { if(DEBUG) { err.println(errconvert(a)); } }
		<T> void errprtln(T a) { if(DEBUG) { err.println(a); } }
		void errprtln(boolean a) { if(DEBUG) { errprtln(a ? "#" : "."); } }
		void errprtln(int... a) {
			if(DEBUG) {
				StringBuilder sb = new StringBuilder();
				for(int element : a){ sb.append(errconvert(element)+" "); }
				errprtln(sb.toString().trim());
			}
		}
		void errprtln(long... a) {
			if(DEBUG) {
				StringBuilder sb = new StringBuilder();
				for(long element : a){ sb.append(errconvert(element)+" "); }
				errprtln(sb.toString().trim());
			}
		}
		void errprtln(double... a) {
			if(DEBUG) {
				StringBuilder sb = new StringBuilder();
				for(double element : a){ sb.append(element+" "); }
				errprtln(sb.toString().trim());
			}
		}
		void errprtln(String... a) {
			if(DEBUG) {
				StringBuilder sb = new StringBuilder();
				for(String element : a){ sb.append(element+" "); }
				errprtln(sb.toString().trim());
			}
		}
		void errprtln(char... a) {
			if(DEBUG) {
				StringBuilder sb = new StringBuilder();
				for(char element : a){ sb.append(element); }
				errprtln(sb.toString().trim());
			}
		}
		void errprtln(boolean... a) {
			if(DEBUG) {
				StringBuilder sb = new StringBuilder();
				for(boolean element : a){ sb.append((element ? "#" : ".")+" "); }
				errprtln(sb.toString().trim());
			}
		}
		void errprtln(int[][] a) { if(DEBUG) { for(int[] element : a){ errprtln(element); } } }
		void errprtln(long[][] a) { if(DEBUG) { for(long[] element : a){ errprtln(element); } } }
		void errprtln(double[][] a) { if(DEBUG) { for(double[] element : a){ errprtln(element); } } }
		void errprtln(String[][] a) { if(DEBUG) { for(String[] element : a){ errprtln(element); } } }
		void errprtln(char[][] a) { if(DEBUG) { for(char[] element : a){ errprtln(element); } } }
		void errprtln(boolean[][] a) { if(DEBUG) { for(boolean[] element : a){ errprtln(element); } } }

		void reply(boolean b) { prtln(b ? "Yes" : "No"); }
		void REPLY(boolean b) { prtln(b ? "YES" : "NO"); }

		void flush() { out.flush(); if(DEBUG) { err.flush(); } }
		void exit() { flush(); System.exit(0); }
		void assertion(boolean b) { if(!b) throw new AssertionError(); }

		int min(int a, int b) { return Math.min(a, b); }
		long min(long a, long b) { return Math.min(a, b); }
		double min(double a, double b) { return Math.min(a, b); }
		int min(int... x) {
			int min = x[0];
			for(int val : x) { min = min(min, val); }
			return min;
		}
		long min(long... x) {
			long min = x[0];
			for(long val : x) { min = min(min, val); }
			return min;
		}
		double min(double... x) {
			double min = x[0];
			for(double val : x) { min = min(min, val); }
			return min;
		}
		int max(int a, int b) { return Math.max(a, b); }
		long max(long a, long b) { return Math.max(a, b); }
		double max(double a, double b) { return Math.max(a, b); }
		int max(int... x) {
			int max = x[0];
			for(int val : x) { max = max(max, val); }
			return max;
		}
		long max(long... x) {
			long max = x[0];
			for(long val : x) { max = max(max, val); }
			return max;
		}
		double max(double... x) {
			double max = x[0];
			for(double val : x) { max = max(max, val); }
			return max;
		}
		long sum(int... a) {
			long sum = 0;
			for(int element : a) { sum += element; }
			return sum;
		}
		long sum(long... a) {
			long sum = 0;
			for(long element : a) { sum += element; }
			return sum;
		}
		double sum(double... a) {
			double sum = 0;
			for(double element : a) { sum += element; }
			return sum;
		}
		long[] sums(int[] a) {
			long sum[] = new long[a.length + 1];
			sum[0] = 0;
			for(int i = 0; i < a.length; i ++) { sum[i + 1] = sum[i] + a[i]; }
			return sum;
		}
		long[] sums(long[] a) {
			long sum[] = new long[a.length + 1];
			sum[0] = 0;
			for(int i = 0; i < a.length; i ++) { sum[i + 1] = sum[i] + a[i]; }
			return sum;
		}
		double[] sums(double[] a) {
			double sum[] = new double[a.length + 1];
			sum[0] = 0;
			for(int i = 0; i < a.length; i ++) { sum[i + 1] = sum[i] + a[i]; }
			return sum;
		}

		int abs(int x) { return x >= 0 ? x : - x; }
		long abs(long x) { return x >= 0 ? x : - x; }
		double abs(double x) { return x >= 0 ? x : - x; }
		int signum(int x) { return x > 0 ? 1 : x < 0 ? -1 : 0; }
		int signum(long x) { return x > 0 ? 1 : x < 0 ? -1 : 0; }
		int signum(double x) { return x > 0 ? 1 : x < 0 ? -1 : 0; }
		long round(double x) { return Math.round(x); }
		long floor(double x) { return (long)Math.floor(x); }
		int divfloor(int a, int b) { return signum(a) == signum(b) ? a / b : - divceil(abs(a), abs(b)); }
		long divfloor(long a, long b) { return signum(a) == signum(b) ? a / b : - divceil(abs(a), abs(b)); }
		long ceil(double x) { return (long)Math.ceil(x); }
		int divceil(int a, int b) { return a >= 0 && b > 0 ? (a + b - 1) / b
											: a < 0 && b < 0 ? divceil(abs(a), abs(b))
											: - divfloor(abs(a), abs(b)); }
		long divceil(long a, long b) { return a >= 0 && b > 0 ? (a + b - 1) / b
											: a < 0 && b < 0 ? divceil(abs(a), abs(b))
											: - divfloor(abs(a), abs(b)); }
		double sqrt(int x) { return Math.sqrt((double)x); }
		double sqrt(long x) { return Math.sqrt((double)x); }
		double sqrt(double x) { return Math.sqrt(x); }
		double pow(double x, double y) { return Math.pow(x, y); }
		long pow(long x, long y) {
			if(y == 0) { return 1;
			}else {
				long tmp = pow(x, y / 2);
				return tmp * tmp * (y % 2 == 0 ? 1 : x);
			}
		}
		int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }
		long gcd(long a, long b) { return b == 0 ? a : gcd(b, a % b); }
		long lcm(long a, long b) { return a / gcd(a, b) * b; }

		int upperToInt(char a) { return a - 'A'; }
		int lowerToInt(char a) { return a - 'a'; }
		int numToInt(char a) { return a - '0'; }
		int charToInt(char a) { return a >= 'a' ? lowerToInt(a) : a >= 'A' ? upperToInt(a) : numToInt(a); }
		char intToUpper(int a) { return (char)(a + 'A'); }
		char intToLower(int a) { return (char)(a + 'a'); }
		char intToNum(int a) { return (char)(a + '0'); }

		long[] div(long a) {
			List<Long> divList = new ArrayList<Long>();
			for(long i = 1; i * i <= a; i ++) {
				if(a % i == 0) {
					divList.add(i);
					if(i * i != a) { divList.add(a / i); };
				}
			}

			long div[] = new long[divList.size()];
			for(int i = 0; i < divList.size(); i ++) { div[i] = divList.get(i); }
			return div;
		}

		long[][] factor(long a) {
			List<Long> factorList = new ArrayList<Long>();
			List<Long> degreeList = new ArrayList<Long>();
			for(long i = 2; i * i <= a; i ++) {
				if(a % i == 0) {
					long count = 0;
					while(a % i == 0) {
						a /= i;
						count ++;
					}
					factorList.add(i);
					degreeList.add(count);
				}
			}
			if(a > 1) {
				factorList.add(a);
				degreeList.add(1L);
			}
			long factor[][] = new long[factorList.size()][2];
			for(int i = 0; i < factorList.size(); i ++) {
				factor[i][0] = factorList.get(i);
				factor[i][1] = degreeList.get(i);
			}
			Arrays.sort(factor, (sort1, sort2) -> Long.compare(sort1[0], sort2[0]));
			return factor;
		}

		boolean isPrime(long x) {
			boolean ok = x > 1;
			for(long i = 2; i * i <= x; i ++) {
				ok &= x % i != 0;
				if(!ok) return ok;
			}
			return ok;
		}
		boolean[] prime(int num) {
			boolean prime[] = new boolean[num];
			fill(prime, true);
			prime[0] = false;
			prime[1] = false;
			for(int i = 2; i < num; i ++) {
				if(prime[i]) {
					for(int j = 2; i * j < num; j ++) {
						prime[i * j] = false;
					}
				}
			}
			return prime;
		}

		long[][] countElements(long[] a, boolean sort) {
			int len = a.length;
			long array[] = new long[len];
			for(int i = 0; i < len; i ++) {
				array[i] = a[i];
			}
			if(sort) { Arrays.sort(array); }
			List<Long> elem = new ArrayList<Long>();
			List<Long> cnt = new ArrayList<Long>();
			long tmp = 1;
			for(int i = 1; i <= len; i ++) {
				if(i == len || array[i] != array[i - 1]) {
					elem.add(array[i - 1]);
					cnt.add(tmp);
					tmp = 1;
				}else {
					tmp ++;
				}
			}
			long counts[][] = new long[elem.size()][2];
			for(int i = 0; i < elem.size(); i ++) {
				counts[i][0] = elem.get(i);
				counts[i][1] = cnt.get(i);
			}
			return counts;
		}
		long[][] countElements(String str, boolean sort) {
			int len = str.length();
			char array[] = str.toCharArray();
			if(sort) { Arrays.sort(array); }
			List<Long> elem = new ArrayList<Long>();
			List<Long> cnt = new ArrayList<Long>();
			long tmp = 1;
			for(int i = 1; i <= len; i ++) {
				if(i == len || array[i] != array[i - 1]) {
					elem.add((long)array[i - 1]);
					cnt.add(tmp);
					tmp = 1;
				}else {
					tmp ++;
				}
			}
			long counts[][] = new long[elem.size()][2];
			for(int i = 0; i < elem.size(); i ++) {
				counts[i][0] = elem.get(i);
				counts[i][1] = cnt.get(i);
			}
			return counts;
		}

		int numDigits(long a) { return Long.toString(a).length(); }
		long bitFlag(int a) { return 1L << (long)a; }
		boolean isFlagged(long x, int a) { return (x & bitFlag(a)) != 0; }

		long countString(String str, String a) { return (str.length() - str.replace(a, "").length()) / a.length(); }
		long countStringAll(String str, String a) { return str.length() - str.replaceAll(a, "").length(); }

		int lowerBound(long array[], long key) {
			return BS(array, key, true, true, true);
		}
		int lowerBound(long array[], long key, int ng, int ok) {
			return BS(array, key, true, true, true, ng, ok);
		}
		int upperBound(long array[], long key) {
			return BS(array, key, true, true, false);
		}
		int upperBound(long array[], long key, int ng, int ok) {
			return BS(array, key, true, true, false, ng, ok);
		}
		int cntBS(long array[], long key, boolean ascending, boolean greater, boolean equals) {
			return BS(array, key, ascending, greater, equals, true);
		}
		int cntBS(long array[], long key, boolean ascending, boolean greater, boolean equals, int ng, int ok) {
			return BS(array, key, ascending, greater, equals, true, ng, ok);
		}
		int BS(long array[], long key, boolean ascending, boolean greater, boolean equals) {
			return BS(array, key, ascending, greater, equals, false);
		}
		int BS(long array[], long key, boolean ascending, boolean greater, boolean equals, int ng, int ok) {
			return BS(array, key, ascending, greater, equals, false, ng, ok);
		}
		int BS(long array[], long key, boolean ascending, boolean greater, boolean equals, boolean count) {
			int ng = ascending ^ greater ? array.length : -1;
			int ok = ascending ^ greater ? -1 : array.length;
			return BS(array, key, ascending, greater, equals, count, ng, ok);
		}
		int BS(long array[], long key, boolean ascending, boolean greater, boolean equals, boolean count, int ng, int ok) {
			int index = binarySearch(array, key, greater, equals, ng, ok);
			return count ? (int)abs(ok - index) : index;
		}
		int binarySearch(long array[], long key, boolean greater, boolean equals, int ng, int ok) {
			while (abs(ok - ng) > 1) {
				int mid = (ok + ng) / 2;
				if(isOKforBinarySearch(array, mid, key, greater, equals)) {
					ok = mid;
				}else {
					ng = mid;
				}
			}
			return ok;
		}
		boolean isOKforBinarySearch(long array[], int index, long key, boolean greater, boolean equals) {
			return (array[index] > key && greater)
				|| (array[index] < key && !greater)
				|| (array[index] == key && equals);
		}

		void reverse(String array[]) {
			String reversed[] = new String[array.length];
			for(int i = 0; i < array.length; i ++) { reversed[array.length - i - 1] = array[i]; }
			for(int i = 0; i < array.length; i ++) { array[i] = reversed[i]; }
		}
		void reverse(int array[]) {
			int reversed[] = new int[array.length];
			for(int i = 0; i < array.length; i ++) { reversed[array.length - i - 1] = array[i]; }
			for(int i = 0; i < array.length; i ++) { array[i] = reversed[i]; }
		}
		void reverse(long array[]) {
			long reversed[] = new long[array.length];
			for(int i = 0; i < array.length; i ++) { reversed[array.length - i - 1] = array[i]; }
			for(int i = 0; i < array.length; i ++) { array[i] = reversed[i]; }
		}
		void reverse(double array[]) {
			double reversed[] = new double[array.length];
			for(int i = 0; i < array.length; i ++) { reversed[array.length - i - 1] = array[i]; }
			for(int i = 0; i < array.length; i ++) { array[i] = reversed[i]; }
		}
		void reverse(boolean array[]) {
			boolean reversed[] = new boolean[array.length];
			for(int i = 0; i < array.length; i ++) { reversed[array.length - i - 1] = array[i]; }
			for(int i = 0; i < array.length; i ++) { array[i] = reversed[i]; }
		}
		void fill(int array[], int x) { Arrays.fill(array, x); }
		void fill(long array[], long x) { Arrays.fill(array, x); }
		void fill(double array[], double x) { Arrays.fill(array, x); }
		void fill(boolean array[], boolean x) { Arrays.fill(array, x); }
		void fill(int array[][], int x) { for(int a[] : array) { fill(a, x); } }
		void fill(long array[][], long x) { for(long a[] : array) { fill(a, x); } }
		void fill(double array[][], double x) { for(double a[] : array) { fill(a, x); } }
		void fill(boolean array[][], boolean x) { for(boolean a[] : array) { fill(a, x); } }
		void fill(int array[][][], int x) { for(int a[][] : array) { fill(a, x); } }
		void fill(long array[][][], long x) { for(long a[][] : array) { fill(a, x); } }
		void fill(double array[][][], double x) { for(double a[][] : array) { fill(a, x); } }
		void fill(boolean array[][][], boolean x) { for(boolean a[][] : array) { fill(a, x); } }

		void shuffleArray(int[] array){
			int n = array.length;
			Random rnd = new Random();
			for(int i = 0; i < n; i ++){
				int tmp = array[i];
				int randomPos = i + rnd.nextInt(n - i);
				array[i] = array[randomPos];
				array[randomPos] = tmp;
			}
		}
		void shuffleArray(long[] array){
			int n = array.length;
			Random rnd = new Random();
			for(int i = 0; i < n; i ++){
				long tmp = array[i];
				int randomPos = i + rnd.nextInt(n - i);
				array[i] = array[randomPos];
				array[randomPos] = tmp;
			}
		}
		void shuffleArray(double[] array){
			int n = array.length;
			Random rnd = new Random();
			for(int i = 0; i < n; i ++){
				double tmp = array[i];
				int randomPos = i + rnd.nextInt(n - i);
				array[i] = array[randomPos];
				array[randomPos] = tmp;
			}
		}

		long INF = (long)1e18 + 7;
		boolean isINF(long a) { return abs(a) > INF / 1000; }
		boolean isPlusINF(long a) { return a > 0 && isINF(a); }
		boolean isMinusINF(long a) { return isPlusINF(- a); }
		int I_INF = (int)1e9 + 7;
		boolean isINF(int a) { return abs(a) > I_INF / 1000; }
		boolean isPlusINF(int a) { return a > 0 && isINF(a); }
		boolean isMinusINF(int a) { return isPlusINF(- a); }


		// mods
		long MOD = (long)1e9 + 7; // 998244353;
		public long mod(long i) { i %= MOD; return i + (i < 0 ? MOD : 0); }

		long pow_m(long x, long y) {
			if(y == 0) { return 1;
			}else {
				long tmp = pow_m(x, y / 2);
				return mod(mod(tmp * tmp) * (y % 2 == 0 ? 1 : x));
			}
		}
		long[] pows_m(long x, int max) {
			long pow[] = new long[max + 1];
			pow[0] = 1;
			for(int i = 0; i < max; i ++) {
				pow[i + 1] = mod(pow[i] * x);
			}
			return pow;
		}

		int MAX_INV_SIZE = 100_100;
		HashMap<Long, Long> invMap = new HashMap<>();
		long inv(long x) {
			x = mod(x);
			if(invMap.containsKey(x)) { return invMap.get(x); }
			if(invMap.size() >= MAX_INV_SIZE) { return calInv(x); }
			invMap.put(x, calInv(x));
			return invMap.get(x);
		}
		long calInv(long x) { return pow_m(x, MOD - 2); }

		int MAX_FACT = 5_000_100;
		long fact[];
		long invFact[];
		boolean isFactPrepared = false;
		HashMap<Integer, long[]> factMap;
		void prepareFact() {
			fact = new long[MAX_FACT];
			Arrays.fill(fact, 0);
			invFact = new long[MAX_FACT];
			Arrays.fill(invFact, 0);
			fact[0] = 1;
			int maxIndex = min(MAX_FACT, (int)MOD);
			for(int i = 1; i < maxIndex; i ++) { fact[i] = mod(fact[i - 1] * i); }
			invFact[maxIndex - 1] = inv(fact[maxIndex - 1]);
			for(int i = maxIndex - 1; i > 0; i --) { invFact[i - 1] = mod(invFact[i] * i); }

			factMap = new HashMap<>();
			isFactPrepared = true;
		}

		long P(int n, int r) {
			if(!isFactPrepared) { prepareFact(); }
			if(n < 0 || r < 0 || n < r) { return 0; }
			if(n >= MAX_FACT) {
				if(!factMap.containsKey(n)) {
					long largeFact[] = new long[MAX_FACT];
					factMap.put(n, largeFact);
					fill(largeFact, -INF);
					largeFact[0] = 1;
				}
				long largeFact[] = factMap.get(n);
				int i = r;
				while(isINF(largeFact[i])) { i --; }
				for(; i < r; i ++) { largeFact[i + 1] = mod(largeFact[i] * (n - i)); }
				return largeFact[r];
			}
			return mod(fact[n] * invFact[n - r]);
		}
		long C(int n, int r) {
			if(!isFactPrepared) { prepareFact(); }
			if(n < 0 || r < 0 || n < r) { return 0; }
			return mod(P(n, r) * invFact[r]);
		}
		long H(int n, int r) { return C((n - 1) + r, r); }


		// grid
		class Grids {
			int h;
			int w;
			Grid[][] gs;
			Grids(int h, int w) {
				this.h = h;
				this.w = w;
				gs = new Grid[h][w];
				for(int i = 0; i < h; i ++) {
					for(int j = 0; j < w; j ++) {
						gs[i][j] = new Grid(i, j, h, w);
					}
				}
			}

			void init(boolean[][] b) {
				for(int i = 0; i < h; i ++) {
					for(int j = 0; j < w; j ++) {
						gs[i][j].b = b[i][j];
					}
				}
			}
			void init(long[][] val) {
				for(int i = 0; i < h; i ++) {
					for(int j = 0; j < w; j ++) {
						gs[i][j].val = val[i][j];
					}
				}
			}

			int dx[] = {0, -1, 1, 0, 0, -1, 1, -1, 1};
			int dy[] = {0, 0, 0, -1, 1, -1, -1, 1, 1};
			Grid next(Grid g, int i) {
				return isValid(g.x + dx[i], g.y + dy[i], g.h, g.w)
					? gs[g.x + dx[i]][g.y + dy[i]]
					: null;
			}
		}
		class Grid implements Comparable<Grid> {
			int x;
			int y;
			int h;
			int w;
			int i;
			boolean b;
			long val;

			Grid() {  }
			Grid(int x, int y, int h, int w) { init(x, y, h, w, false, 0); }
			Grid(int x, int y, int h, int w, boolean b) { init(x, y, h, w, b, 0); }
			Grid(int x, int y, int h, int w, long val) { init(x, y, h, w, false, val); }
			Grid(int x, int y, int h, int w, boolean b, long val) { init(x, y, h, w, b, val); }

			void init(int x, int y, int h, int w, boolean b, long val) {
				this.x = x;
				this.y = y;
				this.h = h;
				this.w = w;
				this.b = b;
				this.val = val;
				i = x * w + y;
			}

			@Override
			public int compareTo(Grid g) {
				return Long.compare(this.val, g.val);
			}
		}

		boolean isValid(int x, int y, int h, int w) {
			return x >= 0 && x < h && y >= 0 && y < w;
		}
		boolean isValid(Grid g) {
			return isValid(g.x, g.y, g.h, g.w);
		}

		// graph
		class Graph {
			int numNode;
			int numEdge;
			boolean directed;
			Edge edges[];
			Node nodes[];
			Node reversedNodes[];

			Graph(int numNode, int numEdge, boolean directed) {
				this.numNode = numNode;
				this.numEdge = numEdge;
				this.directed = directed;
				nodes = new Node[numNode];
				reversedNodes = new Node[numNode];
				for(int i = 0; i < numNode; i ++) {
					nodes[i] = new Node(i);
					reversedNodes[i] = new Node(i);
				}
			}

			void init(Edge edges[]) {
				this.edges = edges;
				for(Edge edge : edges) {
					nodes[edge.source].add(edge.target, edge.cost);
					if(directed) {
						reversedNodes[edge.target].add(edge.source, edge.cost);
					}else {
						nodes[edge.target].add(edge.source, edge.cost);
					}
				}
			}

			void clearNodes() {
				for(Node n : nodes) { n.clear(); }
				for(Node n : reversedNodes) { n.clear(); }
			}
		}

		class Node extends ArrayList<Edge> {
			int id;

			Node(int id) {
				this.id = id;
			}
			void add(int target, long cost) {
				add(new Edge(id, target, cost));
			}
		}

		class Edge implements Comparable<Edge> {
			int source;
			int target;
			long cost;
			Edge(int source, int target, long cost) {
				this.source = source;
				this.target = target;
				this.cost = cost;
			}

			@Override
			public int compareTo(Edge e) {
				return Long.compare(this.cost, e.cost);
			}
		}

public void solve() {
	int numNode = ni();
	int numEdge = ni();
	long ll = nl();
	Graph g = new Graph(numNode, numEdge, false);
	Edge edges[] = new Edge[numEdge];
	for(int i = 0; i < numEdge; i ++) {
		int a = ni() - 1;
		int b = ni() - 1;
		long c = nl();
		edges[i] = new Edge(a, b, c);
	}
	g.init(edges);
	long dist[][] = new long[numNode][numNode];
	for(int i = 0; i < numNode; i ++) {
		dist[i] = dijkstra(g.nodes, i, ll);
	}
	errprtln(dist);
	int q = ni();
	for(int query = 0; query < q; query ++) {
		int s = ni() - 1;
		int t = ni() - 1;
		long ans = (dist[s][t] - 1) / ll;
		prtln(isINF(ans) ? -1 : ans);
	}
}

int prev[];
long[] dijkstra(Node nodes[], int start, long ll) { // O((E+V)logV)
	long dist[] = new long[nodes.length];
	Arrays.fill(dist, INF);
	dist[start] = 0;

	prev = new int[nodes.length];

	Queue<Edge> q = new PriorityQueue<Edge>();
	q.add(new Edge(start, start, dist[start]));

	while(!q.isEmpty()) {
		Edge crt = q.poll();

		if(dist[crt.target] < crt.cost) { continue; }
		for(Edge e : nodes[crt.target]) {
			if(e.cost > ll) continue;
			long cost = dist[e.source] % ll + e.cost;
			if(cost > ll) { cost = ll + e.cost; }
			cost += dist[e.source] / ll * ll;
			if(dist[e.target] > cost) {
				dist[e.target] = cost;
				q.add(new Edge(e.source, e.target, dist[e.target]));
				prev[e.target] = e.source;
			}
		}
	}

	return dist;
}

	}
}