Language: C++

using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Runtime.CompilerServices;
using System.Text;
using static Template;
using static System.Console;
using static System.Convert;
using static System.Math;
using Pi = Pair<int, int>;
//using Graph;
//using DataStructure;

class Solver
{
    public void Solve()
    {
        int num, m, l;
        Input.Make(out num, out m, out l);
        var edge = Input.edge<Pair<int, int>>(num);
        for(var i = 0; i < m; i++)
        {
            int a, b, c;
            Input.Make(out a, out b, out c);
            a--;b--;
            if (c > l) continue;
            edge[a].Add(new Pair<int, int>(c, b));
            edge[b].Add(new Pair<int, int>(c, a));
        }
        var dist = Create(num, () => Create(num, () => new Pair<int,int>(int.MaxValue,0)));
        for(var i = 0; i < num; i++)
        {
            var pq = new PriorityQueue<Pair<int,int,int>>(false);
            pq.Enqueue(new Pair<int, int, int>(0, -l, i));
            dist[i][i] = new Pi(0, -l);
            while (pq.Count != 0)
            {
                var p = pq.Dequeue();
                if ((p.v1 > dist[i][p.v3].v1) || (p.v1 == dist[i][p.v3].v1 && p.v2 > dist[i][p.v3].v2)) continue;
                foreach (var e in edge[p.v3])
                {
                    Pi n;
                    if (p.v2 + e.v1 > 0)
                        n = new Pi(p.v1 + 1, -l + e.v1);
                    else n = new Pi(p.v1, p.v2 + e.v1);
                    if (chmin(ref dist[i][e.v2], n))
                        pq.Enqueue(new Pair<int, int, int>(n.v1, n.v2, e.v2));

                }
            }
        }
        var q = Input.num;
        while (q-- > 0)
        {
            int s, t;
            Input.Make(out s, out t);
            s--;t--;
            WriteLine(dist[s][t].v1==int.MaxValue?-1: dist[s][t].v1);
        }
    }
    
}

public class PriorityQueue<T> where T : IComparable<T>
{
    public List<T> _item;
    public int Count { get { return _item.Count; } }
    public bool IsMaxHeap { get; set; }
    public T Peek { get { return _item[0]; } }
    public PriorityQueue(bool IsMaxHeap = true, IEnumerable<T> list = null)
    {
        _item = new List<T>();
        this.IsMaxHeap = IsMaxHeap;
        if (list != null)
        {
            _item.AddRange(list);
            Build();
        }
    }
    private int Compare(int i, int j) => (IsMaxHeap ? 1 : -1) * _item[i].CompareTo(_item[j]);
    private void Swap(int i, int j) { var t = _item[i]; _item[i] = _item[j]; _item[j] = t; }
    private int Parent(int i)
        => (i - 1) >> 1;
    private int Left(int i)
        => (i << 1) + 1;
    public T Enqueue(T val)
    {
        int i = _item.Count;
        _item.Add(val);
        while (i > 0)
        {
            int p = Parent(i);
            if (Compare(i, p) > 0)
                Swap(i, p);
            i = p;
        }
        return val;
    }
    private void Heapify(int index)
    {
        for (int i = index, j; (j = Left(i)) < _item.Count; i = j)
        {
            if (j != _item.Count - 1 && Compare(j, j + 1) < 0) j++;
            if (Compare(i, j) < 0)
                Swap(i, j);
        }
    }
    public T Dequeue()
    {
        T val = _item[0];
        _item[0] = _item[_item.Count - 1];
        _item.RemoveAt(_item.Count - 1);
        Heapify(0);
        return val;
    }
    private void Build()
    {
        for (var i = (_item.Count >> 1) - 1; i >= 0; i--)
            Heapify(i);
    }
}

public class Template
{
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static bool chmin<T>(ref T num, T val) where T : IComparable<T>
    { if (num.CompareTo(val) == 1) { num = val; return true; } return false; }
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static bool chmax<T>(ref T num, T val) where T : IComparable<T>
    { if (num.CompareTo(val) == -1) { num = val; return true; } return false; }
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static void swap<T>(ref T v1, ref T v2)
    { var t = v2; v2 = v1; v1 = t; }
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static T[] Create<T>(int n, Func<T> f)
        => Enumerable.Repeat(0, n).Select(_ => f()).ToArray();
    public static void Fail() => Fail("No");
    public static void Fail<T>(T s) { WriteLine(s); Console.Out.Close(); Environment.Exit(0); }
    static void Main(string[] args)
    {
        var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
        Console.SetOut(sw);
        var p = new Solver();
        for (var i = 1; i > 0; --i)
            p.Solve();
        Console.Out.Flush();
    }
}

public class Input
{
    public static string read => ReadLine().Trim();
    public static int[] ar => read.Split(' ').Select(int.Parse).ToArray();
    public static int num => ToInt32(read);
    public static long[] arL => read.Split(' ').Select(long.Parse).ToArray();
    public static long numL => ToInt64(read);
    public static char[][] grid(int h)
        => Create(h, () => read.ToCharArray());
    public static int[] ar1D(int n)
        => Create(n, () => num);
    public static long[] arL1D(int n)
        => Create(n, () => numL);
    public static string[] strs(int n)
        => Create(n, () => read);
    public static int[][] ar2D(int n)
        => Create(n, () => ar);
    public static long[][] arL2D(int n)
        => Create(n, () => arL);
    public static List<T>[] edge<T>(int n)
        => Create(n, () => new List<T>());
    public static void Make<T1, T2>(out T1 v1, out T2 v2)
    {
        v1 = Next<T1>();
        v2 = Next<T2>();
    }
    public static void Make<T1, T2, T3>(out T1 v1, out T2 v2, out T3 v3)
    {
        Make(out v1, out v2);
        v3 = Next<T3>();
    }
    public static void Make<T1, T2, T3, T4>(out T1 v1, out T2 v2, out T3 v3, out T4 v4)
    {
        Make(out v1, out v2, out v3);
        v4 = Next<T4>();
    }
    public static void Make<T1, T2, T3, T4, T5>(out T1 v1, out T2 v2, out T3 v3, out T4 v4, out T5 v5)
    {
        Make(out v1, out v2, out v3, out v4);
        v5 = Next<T5>();
    }
    public static void Make<T1, T2, T3, T4, T5, T6>(out T1 v1, out T2 v2, out T3 v3, out T4 v4, out T5 v5, out T6 v6)
    {
        Make(out v1, out v2, out v3, out v4, out v5);
        v6 = Next<T6>();
    }
    static Input()
    {
        sc = new Queue<string>();
        dic = new Dictionary<Type, Func<string, object>>();
        dic[typeof(int)] = s => int.Parse(s);
        dic[typeof(long)] = s => long.Parse(s);
        dic[typeof(char)] = s => char.Parse(s);
        dic[typeof(double)] = s => double.Parse(s);
        dic[typeof(uint)] = s => uint.Parse(s);
        dic[typeof(ulong)] = s => ulong.Parse(s);
        dic[typeof(string)] = s => s;
    }
    private static Dictionary<Type, Func<string, object>> dic;
    private static Queue<string> sc;
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static T Next<T>() { if (sc.Count == 0) foreach (var item in read.Split(' ')) sc.Enqueue(item); return (T)dic[typeof(T)](sc.Dequeue()); }
    public const int MOD = 1000000007;
}

public class Pair<T1, T2> : IComparable<Pair<T1, T2>>
{
    public T1 v1 { get; set; }
    public T2 v2 { get; set; }
    public Pair() { v1 = Input.Next<T1>(); v2 = Input.Next<T2>(); }
    public Pair(T1 v1, T2 v2)
    { this.v1 = v1; this.v2 = v2; }

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public int CompareTo(Pair<T1, T2> p)
    {
        var c = Comparer<T1>.Default.Compare(v1, p.v1);
        if (c == 0)
            c = Comparer<T2>.Default.Compare(v2, p.v2);
        return c;
    }
    public override string ToString()
        => $"{v1.ToString()} {v2.ToString()}";
}

public class Pair<T1, T2, T3> : Pair<T1, T2>, IComparable<Pair<T1, T2, T3>>
{
    public T3 v3 { get; set; }
    public Pair() : base() { v3 = Input.Next<T3>(); }
    public Pair(T1 v1, T2 v2, T3 v3) : base(v1, v2)
    { this.v3 = v3; }

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public int CompareTo(Pair<T1, T2, T3> p)
    {
        var c = base.CompareTo(p);
        if (c == 0)
            c = Comparer<T3>.Default.Compare(v3, p.v3);
        return c;
    }
    public override string ToString()
        => $"{base.ToString()} {v3.ToString()}";
}


Compiler output:
a.cc:1:7: error: expected nested-name-specifier before 'System'
    1 | using System;
      |       ^~~~~~
a.cc:2:7: error: expected nested-name-specifier before 'System'
    2 | using System.Collections.Generic;
      |       ^~~~~~
a.cc:3:7: error: expected nested-name-specifier before 'System'
    3 | using System.Linq;
      |       ^~~~~~
a.cc:4:7: error: expected nested-name-specifier before 'System'
    4 | using System.IO;
      |       ^~~~~~
a.cc:5:7: error: expected nested-name-specifier before 'System'
    5 | using System.Runtime.CompilerServices;
      |       ^~~~~~
a.cc:6:7: error: expected nested-name-specifier before 'System'
    6 | using System.Text;
      |       ^~~~~~
a.cc:7:7: error: expected nested-name-specifier before 'static'
    7 | using static Template;
      |       ^~~~~~
a.cc:8:7: error: expected nested-name-specifier before 'static'
    8 | using static System.Console;
      |       ^~~~~~
a.cc:9:7: error: expected nested-name-specifier before 'static'
    9 | using static System.Convert;
      |       ^~~~~~
a.cc:10:7: error: expected nested-name-specifier before 'static'
   10 | using static System.Math;
      |       ^~~~~~
a.cc:11:12: error: 'Pair' does not name a type
   11 | using Pi = Pair<int, int>;
      |            ^~~~
a.cc:17:11: error: expected ':' before 'void'
   17 |     public void Solve()
      |           ^~~~~
      |           :
a.cc:63:2: error: expected ';' after class definition
   63 | }
      |  ^
      |  ;
a.cc: In member function 'void Solver::Solve()':
a.cc:20:9: error: 'Input' was not declared in this scope
   20 |         Input.Make(out num, out m, out l);
      |         ^~~~~
a.cc:20:20: error: 'out' was not declared in this scope
   20 |         Input.Make(out num, out m, out l);
      |                    ^~~
a.cc:20:33: error: expected ')' before 'm'
   20 |         Input.Make(out num, out m, out l);
      |                                 ^
a.cc:20:19: note: to match this '('
   20 |         Input.Make(out num, out m, out l);
      |                   ^
a.cc:20:40: error: expected ')' before 'l'
   20 |         Input.Make(out num, out m, out l);
      |                                        ^
a.cc:20:19: note: to match this '('
   20 |         Input.Make(out num, out m, out l);
      |                   ^
a.cc:21:9: error: 'var' was not declared in this scope
   21 |         var edge = Input.edge<Pair<int, int>>(num);
      |         ^~~
a.cc:22:17: error: expected ';' before 'i'
   22 |         for(var i = 0; i < m; i++)
      |                 ^
a.cc:22:24: error: 'i' was not declared in this scope
   22 |         for(var i = 0; i < m; i++)
      |                        ^
a.cc:25:28: error: expected ')' before 'a'
   25 |             Input.Make(out a, out b, out c);
      |                            ^
a.cc:25:23: note: to match this '('
   25 |             Input.Make(out a, out b, out c);
      |                       ^
a.cc:25:35: error: expected ')' before 'b'
   25 |             Input.Make(out a, out b, out c);
      |                                   ^
a.cc:25:23: note: to match this '('
   25 |             Input.Make(out a, out b, out c);
      |                       ^
a.cc:25:42: error: expected ')' before 'c'
   25 |             Input.Make(out a, out b, out c);
      |                                          ^
a.cc:25:23: note: to match this '('
   25 |             Input.Make(out a, out b, out c);
      |                       ^
a.cc:28:13: error: 'edge' was not declared in this scope
   28 |             edge[a].Add(new Pair<int, int>(c, b));
      |             ^~~~
a.cc:28:29: error: 'Pair' does not name a type
   28 |             edge[a].Add(new Pair<int, int>(c, b));
      |                             ^~~~
a.cc:28:34: error: expected primary-expression before 'int'
   28 |             edge[a].Add(new Pair<int, int>(c, b));
      |                                  ^~~
a.cc:28:39: error: expected primary-expression before 'int'
   28 |             edge[a].Add(new Pair<int, int>(c, b));
      |                                       ^~~
a.cc:29:29: error: 'Pair' does not name a type
   29 |             edge[b].Add(new Pair<int, int>(c, a));
      |                             ^~~~
a.cc:29:34: error: expected primary-expression before 'int'
   29 |             edge[b].Add(new Pair<int, int>(c, a));
      |                                  ^~~
a.cc:29:39: error: expected primary-expression before 'int'
   29 |             edge[b].Add(new Pair<int, int>(c, a));
      |                                       ^~~
a.cc:31:13: error: expected ';' before 'dist'
   31 |         var dist = Create(num, () => Create(num, () => new Pair<int,int>(int.MaxValue,0)));
      |             ^~~~
a.cc:32:17: error: expected ';' before 'i'
   32 |         for(var i = 0; i < num; i++)
      |                 ^
a.cc:32:24: error: 'i' was not declared in this scope
   32 |         for(var i = 0; i < num; i++)
      |                        ^
a.cc:34:17: error: expected ';' before 'pq'
   34 |             var pq = new PriorityQueue<Pair<int,int,int>>(false);
      |                 ^~
a.cc:35:13: error: 'pq' was not declared in this scope
   35 |             pq.Enqueue(new Pair<int, int, int>(0, -l, i));
      |             ^~
a.cc:35:28: error: 'Pair' does not name a type
   35 |             pq.Enqueue(new Pair<int, int, int>(0, -l, i));
      |                            ^~~~
a.cc:35:33: error: expected primary-expression before 'int'
   35 |             pq.Enqueue(new Pair<int, int, int>(0, -l, i));
      |                                 ^~~
a.cc:35:38: error: expected primary-expression before 'int'
   35 |             pq.Enqueue(new Pair<int, int, int>(0, -l, i));
      |                                      ^~~
a.cc:35:43: error: expected primary-expression before 'int'
   35 |             pq.Enqueue(new Pair<int, int, int>(0, -l, i));
      |                                           ^~~
a.cc:36:13: error: 'dist' was not declared in this scope
   36 |             dist[i][i] = new Pi(0, -l);
      |             ^~~~
a.cc:36:30: error: expected type-specifier before 'Pi'
   36 |             dist[i][i] = new Pi(0, -l);
      |                              ^~
a.cc:39:21: error: expected ';' before 'p'
   39 |                 var p = pq.Dequeue();
      |                     ^
a.cc:40:22: error: 'p' was not declared in this scope
   40 |                 if ((p.v1 > dist[i][p.v3].v1) || (p.v1 == dist[i][p.v3].v1 && p.v2 > dist[i][p.v3].v2)) continue;
      |                      ^
a.cc:41:30: error: expected ')' before 'e'
   41 |                 foreach (var e in edge[p.v3])
      |                              ^
a.cc:41:25: note: to match this '('
   41 |                 foreach (var e in edge[p.v3])
      |                         ^
a.cc:41:17: error: 'foreach' was not declared in this scope
   41 |                 foreach (var e in edge[p.v3])
      |                 ^~~~~~~
a.cc:53:13: error: expected ';' before 'q'
   53 |         var q = Input.num;
      |             ^
a.cc:54:16: error: 'q' was not declared in this scope
   54 |         while (q-- > 0)
      |                ^
a.cc:57:28: error: expected ')' before 's'
   57 |             Input.Make(out s, out t);
      |                            ^
a.cc:57:23: note: to match this '('
   57 |             Input.Make(out s, out t);
      |                       ^
a.cc:57:35: error: expected ')' before 't'
   57 |             Input.Make(out s, out t);
      |                                   ^
a.cc:57:23: note: to match this '('
   57 |             Input.Make(out s, out t);
      |                       ^
a.cc:59:23: error: 'dist' was not declared in this scope
   59 |             WriteLine(dist[s][t].v1==int.MaxValue?-1: dist[s][t].v1);
      |                       ^~~~
a.cc:59:38: error: expected primary-expression before 'int'
   59 |             WriteLine(dist[s][t].v1==int.MaxValue?-1: dist[s][t].v1);
      |                                      ^~~
a.cc:59:13: error: 'WriteLine' was not declared in this scope
   59 |             WriteLine(dist[s][t].v1==int.MaxValue?-1: dist[s][t].v1);
      |             ^~~~~~~~~
a.cc: At global scope:
a.cc:65:1: error: expected unqualified-id before 'public'
   65 | public class PriorityQueue<T> where T : IComparable<T>
      | ^~~~~~
a.cc:124:1: error: expected unqualified-id before 'public'
  124 | public class Template
      | ^~~~~~
a.cc:151:1: error: expected unqualified-id before 'public'
  151 | public class Input
      | ^~~~~~
a.cc:216:1: error: expected unqualified-id before 'public'
  216 | public class Pair<T1, T2> : IComparable<Pair<T1, T2>>
      | ^~~~~~
a.cc:236:1: error: expected unqualified-id before 'public'
  236 | public class Pair<T1, T2, T3> : Pair<T1, T2>, IComparable<Pair<T1, T2, T3>>
      | ^~~~~~