CSES - Shared codeLink to this code:
https://cses.fi/paste/9d1a799e3b1f7f1a2eddec/
/*
=============================================================================
/\ \ / /\ |\ /| |===========
/ \ \ / / \ | \ / | |
/ \ \ / / \ | \ / | |
/ \ | / \ | \ / | |===========
/--------\ | /--------\ | \ / | |
/ \ | / \ | \ / | |
/ \ | / \ | | | |===========
A A
AAAAAAAA AAA AAAA A A A A A A
A A A A A A A A A A A A A
A A AA A A A A A A A A A
A A A AA A A A A A A A
A AAA A A AAA AAA AAAAA
=============================================================================
*/
#include<bits/stdc++.h>
#define pb push_back
#define pf push_front
#define mp make_pair
#define F first
#define S second
#define pq priority_queue
#define ll long long int
#define pii pair<int,int>
#define endl '\n'
#define Orz ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define MAXN 200001
using namespace std;
//YeedragOrz
//8e7Orz
//jassOrz
//FHvirusOrz
//samOrz
//yungyaoOrz
//littlecubeOrz
//2qbingxuanOrz
//FoodSheepOrz
//ck_platypusOrz
//koyingOrz
//foxyyOrz
//peiganOrz
//jikuaiOrz
vector<int> dis[MAXN];
bitset<MAXN> match=0,vis=0;
int dfs(int n){
vis[n]=1;
int sum=0,flag=0;
for(auto i:dis[n]){
if(vis[i]==0){
sum+=dfs(i);
if(match[i]==0)flag=1;
}
}
if(match[n]==0&&flag==1){
match[n]=1;sum++;
}
return sum;
}
int main(){
int n;
cin>>n;
for(int i=1;i<n;i++){
int a,b;cin>>a>>b;
dis[a].pb(b);
dis[b].pb(a);
}
cout<<dfs(1)<<endl;
return 0 ;
}