using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using static System.Console;
using static System.Convert;
using static System.Math;
//using static System.Globalization.CultureInfo;
using System.Text;
class Program
{
    private static void chmin<T>(ref T num, T val) where T : IComparable<T>
        => num = num.CompareTo(val) == 1 ? val : num;
    private static void chmax<T>(ref T num, T val) where T : IComparable<T>
        => num = num.CompareTo(val) == -1 ? val : num;
    static void Main(string[] args)
    {
        var pr = new Program();
        var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
        Console.SetOut(sw);
        pr.Solve();
        Console.Out.Flush();
    }
    int num, m, s, t;
    List<Pair<long, int>>[] edge;
    long[] dist;
    long[] memo1, memo2;
    void Solve()
    {
        Input.Make(out num, out m, out s, out t);
        s--; t--;
        edge = Input.edge<Pair<long, int>>(num);
        while (m-- > 0)
        {
            var uvd = Input.ar;
            for (var j = 0; j < 2; j++)
                edge[uvd[j] - 1].Add(new Pair<long, int>(uvd[2], uvd[1 ^ j] - 1));
        }
        dist = Dijkstra(edge, s);
        memo1 = Enumerable.Repeat(-1L, num).ToArray();
        memo2 = Enumerable.Repeat(-1L, num).ToArray();
        memo1[s] = memo2[t] = 1;
        dp1(t); dp2(s);
        var res = (ModInt)memo1[t] * memo1[t];
        for (var i = 0; i < num; i++)
            if (dist[t] == dist[i] * 2)
                res -= (ModInt)memo1[i] * memo1[i] * memo2[i] * memo2[i];
        for(var i=0;i<num;i++)
            foreach (var ad in edge[i])
            {
                if (dist[i] > dist[ad.v2]) continue;
                if (dist[i] * 2 >= dist[t] || dist[ad.v2] * 2 <= dist[t] || dist[i] + ad.v1 != dist[ad.v2]) continue;
                res -= (ModInt)memo1[i] * memo1[i] * memo2[ad.v2] * memo2[ad.v2];
            }
        WriteLine(res);
    }
    public static long[] Dijkstra(IList<IEnumerable<Pair<long, int>>> edges, int st)
    {
        var dist = Enumerable.Repeat(long.MaxValue, edges.Count).ToArray();
        var pq = new PriorityQueue<Pair<long, int>>(false);
        pq.Enqueue(new Pair<long, int>(0, st));
        dist[st] = 0;
        while (pq.Count != 0)
        {
            var p = pq.Dequeue();
            if (dist[p.v2] < p.v1) continue;
            foreach (var e in edges[p.v2])
                if (dist[e.v2] > e.v1 + dist[p.v2])
                {
                    dist[e.v2] = e.v1 + dist[p.v2];
                    pq.Enqueue(new Pair<long, int>(dist[e.v2], e.v2));
                }
        }
        return dist;
    }
    long dp1(int index)
    {
        if (memo1[index] != -1) return memo1[index];
        var ct = 0L;
        foreach (var ad in edge[index])
            if (dist[ad.v2] + ad.v1 == dist[index])
                ct = (ct + dp1(ad.v2)) % Input.MOD;
        return memo1[index] = ct;
    }
    long dp2(int index)
    {
        if (memo2[index] != -1) return memo2[index];
        var ct = 0L;
        foreach (var ad in edge[index])
            if (dist[ad.v2] == ad.v1 + dist[index])
                ct = (ct + dp2(ad.v2)) % Input.MOD;
        return memo2[index] = ct;
    }
}

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 T[] create<T>(int n, Func<int, T> f)
        => Enumerable.Repeat(0, n).Select(f).ToArray();
    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 T GetValue<T>(string g)
    {
        var t = typeof(T);
        if (t == typeof(int))
            return (T)(object)int.Parse(g);
        if (t == typeof(long))
            return (T)(object)long.Parse(g);
        if (t == typeof(string))
            return (T)(object)g;
        if (t == typeof(char))
            return (T)(object)char.Parse(g);
        if (t == typeof(double))
            return (T)(object)double.Parse(g);
        if (t == typeof(bool))
            return (T)(object)bool.Parse(g);
        return default(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>();
    }
    private static Queue<string> sc;
    public static T Next<T>(){ sc = sc ?? new Queue<string>(); if (sc.Count == 0) foreach (var item in read.Split(' ')) sc.Enqueue(item);return GetValue<T>(sc.Dequeue()); }
    public static void Next<T>(ref T val) => val = Next<T>(); 
    public const long Inf = (long)1e18;
    public const double eps = 1e-6;
    public const string Alfa = "abcdefghijklmnopqrstuvwxyz";
    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; }

    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 override bool Equals(object obj)
        => this == (Pair<T1, T2>)obj;
    public override int GetHashCode()
        => v1.GetHashCode() ^ v2.GetHashCode();
    public static bool operator ==(Pair<T1, T2> p1, Pair<T1, T2> p2)
        => p1.CompareTo(p2) == 0;
    public static bool operator !=(Pair<T1, T2> p1, Pair<T1, T2> p2)
        => p1.CompareTo(p2) != 0;
    public static bool operator >(Pair<T1, T2> p1, Pair<T1, T2> p2)
        => p1.CompareTo(p2) == 1;
    public static bool operator >=(Pair<T1, T2> p1, Pair<T1, T2> p2)
        => p1.CompareTo(p2) != -1;
    public static bool operator <(Pair<T1, T2> p1, Pair<T1, T2> p2)
        => p1.CompareTo(p2) == -1;
    public static bool operator <=(Pair<T1, T2> p1, Pair<T1, T2> p2)
        => p1.CompareTo(p2) != 1;
}

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; }

    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()}";
}

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 struct ModInt
{
    public const long MOD = (int)1e9 + 7;
    //public const long MOD = 998244353;
    public long num { get; set; }
    public ModInt(long n = 0) { num = n; }
    private static ModInt[] _fac;//階乗
    private static ModInt[] _inv;//逆数
    private static ModInt[] _facrev;//1/(i!)
    public override string ToString()
        => num.ToString();
    public static ModInt operator +(ModInt l, ModInt r)
    {
        l.num += r.num;
        if (l.num >= MOD) l.num -= MOD;
        return l;
    }
    public static ModInt operator -(ModInt l, ModInt r)
    {
        l.num -= r.num;
        if (l.num < 0) l.num += MOD;
        return l;
    }
    public static ModInt operator *(ModInt l, ModInt r)
        => new ModInt(l.num * r.num % MOD);
    public static ModInt operator /(ModInt l, ModInt r)
        => l * Pow(r, MOD - 2);
    public static implicit operator long(ModInt l)
        => l.num;
    public static implicit operator ModInt(long n)
    {
        n %= MOD; if (n < 0) n += MOD;
        return new ModInt(n);
    }

    public static ModInt Pow(ModInt m, long n)
    {
        if (n == 0) return 1;
        if (n % 2 == 0) return Pow(m * m, n >> 1);
        else return Pow(m * m, n >> 1) * m;
    }

    public static void CombBuild(int n)
    {
        _fac = new ModInt[n + 1];
        _facrev = new ModInt[n + 1];
        _inv = new ModInt[n + 1];
        _inv[1] = 1;
        _fac[0] = _fac[1] = 1;
        _facrev[0] = _facrev[1] = 1;
        for (var i = 2; i <= n; i++)
        {
            _fac[i] = _fac[i - 1] * i;
            _inv[i] = MOD - _inv[MOD % i] * (MOD / i);
            _facrev[i] = _facrev[i - 1] * _inv[i];
        }
    }

    public static ModInt Fac(ModInt n)
        => _fac[n];
    public static ModInt Div(ModInt n)
        => _inv[n];
    public static ModInt FacRev(ModInt n)
        => _facrev[n];
    public static ModInt Part(ModInt n, ModInt r)
    {
        if (n < r) return 0;
        return _fac[n] * _facrev[n - r];
    }
    public static ModInt Comb(ModInt n, ModInt r)
    {
        if (n < r) return 0;
        if (n == r) return 1;
        var calc = _fac[n];
        calc = calc * _facrev[r];
        calc = calc * _facrev[n - r];
        return calc;
    }
}




Measured memory_bytes: 60928