Shared code

#include<bits/stdc++.h>
using namespace std;
 
typedef long long int ll;
#define IOS ios_base::sync_with_stdio(0);  cin.tie(0); cout.tie(0);
 
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
 
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>order_set;
typedef pair<int, int>pr;
#define all(i)     i.begin() , i.end()
#define ft     first
#define sn     second
#define pb push_back
 
#define totalone(mask) __builtin_popcount(mask)
#define chkbit(mask,bit) (mask&(1LL << bit))
#define setbit(mask,bit) (mask|(1LL << bit))
#define cngbit(mask,bit) (mask^(1LL << bit))
 
#define en "\n"
#define dbg(x) cerr<<#x<<" is : "<<x<<en;
#define yes cout<<"YES\n"
#define no cout<<"NO\n"
#define report cout<<-1<<en
#define sum(n) ((1LL*(n)*(n+1))/ 2LL)
#define sqr(n) (1LL*(n)*(n))
#define vag(a,b) ((a + b - 1)/b)
#define coutv(v) for(auto i: v) cout<<i<<" ";cout<<en;
#define cinv(v) for(auto &i: v) cin >> i;
 
const int MAXN = 200005;
#define inf 1e15
const int mod = 1e9 + 7;
 
int n;
vector<int>g[MAXN];
int vis[MAXN];
int col[MAXN];
int an;
 
void dfs(int nd, int p)
{
    vis[nd] = 1;
 
    for (auto i : g[nd])
    {
        if (vis[i]) continue;
        dfs(i, nd);
    }
 
    if (col[nd] == 0 && col[p] == 0 && p != 0) {
        // cout << nd << " " << p << en;
        col[nd] = col[p] = 1;
        an++;
    }
 
}
void solve()
{
    cin >> n;
    for (int i = 1; i < n; i++)
    {
        int x, y;
        cin >> x >> y;
        g[x].pb(y);
        g[y].pb(x);
    }
 
    dfs(1, 0);
    // dbg(an);
 
    cout << an << en;
}
int main()
{
    IOS;
    ll t;
    t = 1;
    // cin >> t;
 
    int c = 0;
    while ( t-- )
    {
        // cout<<"Case "<<++c<<": ";
        solve();
    }
    return 0;
}