#include "closing.h"
#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <vector>
#include <queue>

typedef long long llong;
const int MAXN = 500 + 10;
const llong INF = 8e18;
const int INTINF = 2e9;

int n;
int x;
int y;
llong k;
int sz[MAXN];
int par[MAXN];
bool isOnPath[MAXN];
int suffixSizes[MAXN];
std::vector <int> path;
std::vector <int> pathSizes;
std::vector <std::pair <int,int>> g[MAXN];
llong dpR[MAXN][2 * MAXN][2][2]; // root
llong dpC[MAXN][2 * MAXN][2][2]; // children, knapsack
llong dpS[MAXN][2 * MAXN][2][2]; // stick
bool blR[MAXN][2 * MAXN][2][2];
bool blC[MAXN][2 * MAXN][2][2];
bool blS[MAXN][2 * MAXN][2][2];
llong distX[MAXN];
llong distY[MAXN];

void reset()
{
    path.clear();
    pathSizes.clear();
    for (int i = 0 ; i < n ; ++i)
    {
        g[i].clear();
        isOnPath[i] = false;
        distX[i] = distY[i] = 0;
        for (int j = 0 ; j <= 2 * n ; ++j)
        {
            for (int flagX = 0 ; flagX < 2 ; ++flagX)
            {
                for (int flagY = 0 ; flagY < 2 ; ++flagY)
                {
                    dpR[i][j][flagX][flagY] = 0;
                    dpC[i][j][flagX][flagY] = 0;
                    dpS[i][j][flagX][flagY] = 0;
                    blR[i][j][flagX][flagY] = false;
                    blC[i][j][flagX][flagY] = false;
                    blS[i][j][flagX][flagY] = false;
                }
            }
        }
    }
}

void dfs(int node, int par, llong to[], llong dist)
{
    to[node] = dist;
    for (const auto &[u, d] : g[node])
    {
        if (u == par)
        {
            continue;
        }

        dfs(u, node, to, dist + d);
    }
}

bool dfsPath(int node, int par)
{
    if (node == y)
    {
        path.push_back(node);
        return true;
    }

    for (const auto &[u, d] : g[node])
    {
        if (u == par)
        {
            continue;
        }

        if (dfsPath(u, node))
        {
            path.push_back(node);
            return true;
        }
    }

    return false;
}

void dfsSize(int node, int p)
{
    sz[node] = 1;
    par[node] = p;
    for (const auto &[u, d] : g[node])
    {
        if (p == u)
        {
            continue;
        }

        dfsSize(u, node);
        if (!isOnPath[u]) sz[node] += sz[u];
    }
}

llong fRoot(int, int, int, int);
llong fChildren(int, int, int, int, int);
llong fStick(int, int, int, int);

llong fRoot(int node, int choose, int flagX, int flagY)
{
    if (choose == 0)
    {
        return 0;
    }

    if (!flagX && !flagY)
    {
        return k + 1;
    }

    if (blR[node][choose][flagX][flagY])
    {
        return dpR[node][choose][flagX][flagY];
    }

    blR[node][choose][flagX][flagY] = true;
    dpR[node][choose][flagX][flagY] = fChildren(node, 0, choose, flagX, flagY);
    dpR[node][choose][flagX][flagY] = std::min(dpR[node][choose][flagX][flagY], k + 1);
    return dpR[node][choose][flagX][flagY];
}

llong fChildren(int node, int idx, int choose, int flagX, int flagY)
{
    if (idx == g[node].size())
    {
        if (choose == 0) return 0;
        return k + 1;
    }

    int current = g[node][idx].first;
    if (isOnPath[current] || current == par[node])
    {
        return fChildren(node, idx + 1, choose, flagX, flagY);
    }

    if (blC[current][choose][flagX][flagY])
    {
        return dpC[current][choose][flagX][flagY];
    }

    blC[current][choose][flagX][flagY] = true;
    dpC[current][choose][flagX][flagY] = k + 1;

    for (int currX = 0 ; currX <= flagX ; ++currX)
    {
        for (int currY = 0 ; currY <= flagY ; ++currY)
        {
            for (int subtreeChoose = std::max(choose - 2 * suffixSizes[(idx + 1 == g[node].size() ? 0 : g[node][idx + 1].first)], currX + currY) ; subtreeChoose <= std::min(2 * sz[g[node][idx].first], choose) ; ++subtreeChoose)
            {
                if (fChildren(node, idx + 1, choose - subtreeChoose, flagX, flagY) > k) continue;
                dpC[current][choose][flagX][flagY] = std::min(dpC[current][choose][flagX][flagY], fChildren(node, idx + 1, choose - subtreeChoose, flagX, flagY) + std::max((currX == 0 ? 0 : distX[current]), (currY == 0 ? 0 : distY[current])) + fRoot(current, subtreeChoose - currX - currY, currX, currY));
            }
        }
    }

    return dpC[current][choose][flagX][flagY];
}

llong fStick(int idx, int choose, int flagX, int flagY)
{
    if (idx == path.size())
    {
        if (choose == 0) return 0;
        return k + 1;
    }

    if (blS[idx][choose][flagX][flagY])
    {
        return dpS[idx][choose][flagX][flagY];
    }

    blS[idx][choose][flagX][flagY] = true;
    dpS[idx][choose][flagX][flagY] = k + 1;
    for (int currX = 0 ; currX <= flagX ; ++currX)
    {
        for (int currY = flagY ; currY < 2 ; ++currY)
        {
            for (int subtreeChoose = std::max(choose - 2 * pathSizes[idx + 1], currX + currY) ; subtreeChoose <= std::min(2 * sz[path[idx]], choose) ; ++subtreeChoose)
            {
                if (fStick(idx + 1, choose - subtreeChoose, currX, currY) > k) continue;
                dpS[idx][choose][flagX][flagY] = std::min(dpS[idx][choose][flagX][flagY], fStick(idx + 1, choose - subtreeChoose, currX, currY) + std::max((currX == 0 ? 0 : distX[path[idx]]), (currY == 0 ? 0 : distY[path[idx]])) + fRoot(path[idx], subtreeChoose - currX - currY, currX, currY));
            }
        }
    }

    return dpS[idx][choose][flagX][flagY];
}

int max_score(int N, int X, int Y, long long K, std::vector <int> U, std::vector <int> V, std::vector <int> W)
{
    reset();
    n = N;
    x = X;
    y = Y;
    k = K;

    for (int i = 0 ; i < n - 1 ; ++i)
    {
        g[U[i]].emplace_back(V[i], W[i]);
        g[V[i]].emplace_back(U[i], W[i]);
    }

    dfs(x, -1, distX, 0);
    dfs(y, -1, distY, 0);
    dfsPath(x, -1);
    dfsSize(x, -1);

    for (int i = 0 ; i < n ; ++i)
    {
        for (int j = g[i].size() - 1 ; j >= 0 ; --j)
        {
            int add = 0;
            suffixSizes[g[i][j].first] = suffixSizes[(j + 1 == g[i].size() ? 0 : g[i][j + 1].first)];
            if (!isOnPath[g[i][j].first] && g[i][j].first != par[i])
            {
                add = sz[g[i][j].first];
            }

            suffixSizes[g[i][j].first] += add;
        }
    }

    std::reverse(path.begin(), path.end());
    for (const int &i : path)
    {
        isOnPath[i] = true;
    }

    pathSizes.resize(path.size() + 1, 0);
    for (int i = path.size() - 1 ; i >= 0 ; --i)
    {
        pathSizes[i] = pathSizes[i + 1] + sz[path[i]];
    }

    for (int i = 2 * n ; i >= 1 ; --i)
    {
        if (fStick(0, i, 1, 0) <= k)
        {
            return i;
        }
    }

    return 0;
}