Tree_Matching

#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/detail/standard_policies.hpp>
#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")

using namespace __gnu_pbds;
using namespace std;
typedef tree<int,null_type,less<int>,rb_tree_tag, tree_order_statistics_node_update> indexed_set;

#define ll long long int
#define fo(i,n) for(i=0;i<n;i++)
#define f0(i,k,n) for(i=k;i<n;i++)
#define fr(i,k,n) for(i=k-1;i>=n;i--)
#define Fo(i,k,n) for(i=k;k<n?i<n:i>n;k<n?i+=1:i-=1)
#define prv(arr) for(auto i:arr)cout<<i<<" ";cout<<'\n';
#define pra(arr,n) for(int i=0;i<n;i++)cout<<arr[i]<<" ";cout<<'\n';
#define si(x) scanf("%d",&x)
#define sl(x) scanf("%lld",&x)
#define ss(s) scanf("%s",s)
#define pi(x) printf("%d\n",x)
#define pl(x) printf("%lld\n",x)
#define ps(s) printf("%s\n",s)
#define setbits(x) __builtin_popcountll(x)
#define endl '\n'
#define nl cout<<endl
#define deb(x) cout << #x << "=" << x << endl
#define deb2(x,y) cout << #x << "=" << x << "," << #y << "=" << y <<endl
#define pb push_back
#define mk make_tuple
#define F first
#define S second
#define lb lower_bound
#define ub upper_bound 
#define MI INT_MIN
#define MX INT_MAX
#define gcd(x,y) __gcd(x,y)
#define all(x) x.begin(), x.end()
#define clr(x) memset(x, 0, sizeof(x))
#define sortall(x) sort(all(x))
#define rev(x) reverse(all(x))
#define tr(it,a) for(auto it = a.begin(); it != a.end(); it++)
#define PI 3.145926535897932384626
#define inf 1e18
#define sp(x,y) fixed<<setprecision(x)<<y   
#define fast() ios_base::sync_with_stdio(false);cin.tie(NULL)
typedef priority_queue<int, vector<int>,greater<int> > pqri;
typedef priority_queue<ll, vector<ll>,greater<ll> > pqrl;
typedef priority_queue<int> pqi;
typedef priority_queue<int> pql;
typedef pair <int,int> pii;
typedef pair <ll,ll> pll;
typedef vector <int> vi;
typedef vector <ll> vl;
typedef vector <pii> vpii;
typedef vector <pll> vpll;
typedef vector <vi> vvi;
typedef vector <vl> vvl;
typedef stack <int> sti;
typedef stack <ll> stl;
typedef queue <int> qi;
typedef queue <ll> ql;
typedef map<int,int> mpi;
typedef map<ll,ll> mpl;

const int mod = 1'000'000'007;
const int N = 3e5, M=N;

int p=1;

ll pw(ll n,ll a)
{
    ll ans = 1;
    while(a)
    {
        if(a&1)
        ans = (n*ans)%mod;
        n = (n*n)%mod;
        a>>=1;
    }
    return ans;
}
ll modInv(ll n, ll p) 
{ 
    return pw(n, p - 2); 
} 

bool prime[10000001];
int call[10000001];
void Sieve(int n)
{
    memset(prime, true, sizeof(prime));
 
    for (int p = 2; p * p <= n; p++)
    {
        if (prime[p] == true)
        {
            for (ll i = p * p; i <= n; i += p)
                prime[i] = false;
        }
    }
 

    for(ll i=2;i<=n;i++)
    if(prime[i])call[i]=call[i-1]+1;
    else call[i]=call[i-1];
}
 

void google(){
    ll i,j,k,m,n,x,y,z,mi,mx,count=0,ans=0;
    
    cout<<"Case #"<<p<<": "<<ans<<endl;
    p++;
    
}
ll match=0;
void dfs(vector<ll> adj[],vector<vector<ll> > &dp,ll cur,ll par,vector<ll> &used)
{
    for(auto i:adj[cur])
    {
        if(i!=par){
            dfs(adj,dp,i,cur,used);
            // dp[cur][0]= max(dp[i][0],dp[i][1]);
            // dp[cur][1]+=dp[i][0]+1;
            
        }
            if(!used[i] && !used[cur] && i!=par){
                used[i]=1;
                used[cur]=1;
                match++;
            }
        
    }
}
void solve(){
    ll i,j,k,m,n,x,y,z,mi,mx,count=0,ans=0,sum=0,ct=0;
    mi=inf;mx=inf;
    string str="",s="",aa="";
    cin>>n;
    vector<ll> adj[n+1];
    fo(i,n-1)
    {
        cin>>x>>y;
        adj[x].pb(y);
        adj[y].pb(x);
    }
    vector<vector<ll> > dp(n+1,vector<ll> (2,0) );
    vector<ll> used(n+1,0);
    dfs(adj,dp,1ll,-1ll,used);
    // cout<<dp[1][0]+dp[1][1]<<endl;
    cout<<match;
    
}

int main() {
    fast();
    // Sieve(10000000);
    // #ifndef ONLINE_JUDGE
    //     freopen("consistency_chapter_1_input.txt", "r", stdin);
    //     freopen("output.txt", "w", stdout);
    // #endif
    int t = 1;
    // cin>>t;
    while(t--) {
        solve();
       // google();
    }
}\