//Author: Kevin
#include<bits/stdc++.h>
//#pragma GCC optimize("O2")
using namespace std;
#define ll long long
#define ull unsigned ll
#define pb emplace_back
#define mp make_pair
#define ALL(x) (x).begin(),(x).end()
#define rALL(x) (x).rbegin(),(x).rend()
#define srt(x) sort(ALL(x))
#define rev(x) reverse(ALL(x))
#define rsrt(x) sort(rALL(x))
#define sz(x) (int)(x.size())
#define inf 0x3f3f3f3f
#define pii pair<int,int>
#define lb(v,x) (int)(lower_bound(ALL(v),x)-v.begin())
#define ub(v,x) (int)(upper_bound(ALL(v),x)-v.begin())
#define uni(v) v.resize(unique(ALL(v))-v.begin())
#define longer __int128_t
void die(string S){puts(S.c_str());exit(0);}
int n,k,m;
vector<pii> G[200200];
int ans;
vector<int> pool;
int siz[200200],mx[200200];
int ban[200200];
void dfs1(int u,int fa)
{
	pool.pb(u);
	siz[u]=1;
	mx[u]=0;
	for(auto pr:G[u])
		if(!ban[pr.first]&&pr.first!=fa)
		{
			dfs1(pr.first,u);
			siz[u]+=siz[pr.first];
			mx[u]=max(mx[u],siz[pr.first]);
		}
}
int sub[200200],rem[200200],cost[200200],val[200200],color[200200];
void dfs2(int u,int fa,int co,int len,int col,int rep,int flag,int rm,int d,int stc)
{
	sub[u]=rep;
	rem[u]=(flag?len%(k+1):rm);
	cost[u]=co+len/(k+1);
	val[u]=d;
	color[u]=stc;
	for(auto pr:G[u])
	{
		int v=pr.first;
		int w=pr.second;
		if(v==fa||ban[v]) continue;
		if(w==col)
			dfs2(v,u,co,len+1,col,rep,flag,rm,d+1,stc);
		else if(flag)
			dfs2(v,u,co+len/(k+1),1,col^1,rep,0,len%(k+1),d+1,stc);
		else
			dfs2(v,u,co+len/(k+1),1,col^1,rep,flag,rm,d+1,stc);
	}
}
void go(int x)
{
	pool.clear();
	dfs1(x,0);
	int p=x;
	for(auto p2:pool)
		if(max(mx[p2],siz[x]-siz[p2])<max(mx[p],siz[x]-siz[p]))
			p=p2;
	x=p;
	for(auto pr:G[x])
		if(!ban[pr.first])
			dfs2(pr.first,x,0,1,pr.second,pr.first,1,-1,1,pr.second);
	for(auto u:pool)
		if(u!=x)
			if(cost[u]<=m)
				ans=max(ans,val[u]);
	vector<array<int,4>> v[2];
	for(auto u:pool)
		if(u!=x)
			v[color[u]].push_back({cost[u],val[u],sub[u],u});
	srt(v[0]);
	rsrt(v[1]);
	int val1=-1,val2=-1;
	int rep1=-1,rep2=-1;
	p=0;
	auto add=[&](int val,int rep)
	{
		if(rep1==rep)
			val1=max(val1,val);
		else if(rep2==rep)
		{
			val2=max(val2,val);
			if(val2>val1)
			{
				swap(val1,val2);
				swap(rep1,rep2);
			}
		}
		else
		{
			if(val>val1)
			{
				swap(val,val1);
				swap(rep,rep1);
			}
			if(val>val2)
			{
				swap(val,val2);
				swap(rep,rep2);
			}
		}
	};
	for(auto arr:v[1])
	{
		while(p<sz(v[0])&&v[0][p][0]+arr[0]<=m)
		{
			add(v[0][p][1],v[0][p][2]);
			p++;
		}
		if(arr[2]!=rep1&&~rep1) ans=max(ans,val1+arr[1]);
		if(arr[2]!=rep2&&~rep2) ans=max(ans,val2+arr[1]);
	}
	rev(v[1]);
	for(int c=0;c<2;c++)
	{
		val1=val2=rep1=rep2=-1;
		p=0;
		for(int i=sz(v[c])-1;i>=0;i--)
		{
			while(p<sz(v[c])&&v[c][p][0]+v[c][i][0]<m)
			{
				add(v[c][p][1],v[c][p][2]);
				p++;
			}
			if(v[c][i][2]!=rep1&&~rep1) ans=max(ans,val1+v[c][i][1]);
			if(v[c][i][2]!=rep2&&~rep2) ans=max(ans,val2+v[c][i][1]);
		}
	}
	for(int c=0;c<2;c++)
	{
		p=0;
		for(int i=sz(v[c])-1;i>=0;i--)
		{
			while(p<sz(v[c])&&v[c][p][0]+v[c][i][0]<m)
				p++;
			int j=i;
			while(j&&v[c][j-1][0]==v[c][j][0]) j--;
			if(p==sz(v[c])||v[c][p][0]+v[c][i][0]!=m)
			{
				i=j;
				continue;
			}
			val1=val2=rep1=rep2=-1;
			vector<int> v1,v2;
			for(int x=j;x<=i;x++) v1.pb(v[c][x][3]);
			int p2=p;
			while(p2<sz(v[c])-1&&v[c][p2+1][0]==v[c][p2][0]) p2++;
			for(int x=p;x<=p2;x++) v2.pb(v[c][x][3]);
			sort(ALL(v1),[&](int A,int B){return rem[A]<rem[B];});
			sort(ALL(v2),[&](int A,int B){return rem[A]>rem[B];});
			int po=0;
			for(auto ind:v2)
			{
				while(po<sz(v1)&&rem[v1[po]]+rem[ind]<=k)
				{
					add(val[v1[po]],sub[v1[po]]);
					po++;
				}
				if(sub[ind]!=rep1&&~rep1) ans=max(ans,val1+val[ind]);
				if(sub[ind]!=rep2&&~rep2) ans=max(ans,val2+val[ind]);
			}
			i=j;
		}
	}
	ban[x]=1;
	for(auto pr:G[x])
		if(!ban[pr.first])
			go(pr.first);
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>k>>m;
	for(int i=1;i<n;i++)
	{
		int u,v,w;
		cin>>u>>v>>w;
		G[u].pb(v,w);
		G[v].pb(u,w);
	}
	go(1);
	cout<<ans<<'\n';
	return 0;
}