#include <bits/stdc++.h>
#define pb push_back
#define sz(x) x.size()
#define F first
#define S second
#define mp make_pair
#define ll long long
#define sqr(x) ((x)*(x))
using namespace std;
    ll a[1010][1010], b[100010], c[10010];
    ll mn=1e9, mx=-1e9, ans, cnt, sm;
    bool ok, okk, u[10000010], uu[10000010];
    ll n, m;
    int x, y;
    vector <int> v;

void dfsx(ll l){
    u[l]=1;
    for(int i=1;i<=n;i++){
        if(a[i][l]==1 && !u[i]){
            v.pb(i);
            dfsx(i);
        }
    }
}
void dfsy(ll r){
    uu[r]=1;
    for(int i=1;i<=n;i++){
        if(a[i][r]==1 && !uu[i]){
            for(int j=0;j<sz(v);j++){
            	if(i==v[j]){
            		ok=true;
            		ans=i;
            		break;
            	}
            }
            if(!ok){
            	dfsy(i);
           	}
        }
        if(ok){
        	break;
        }
    }
}


int main(){

    freopen ("input.txt","r",stdin);
    freopen ("output.txt","w",stdout);

    cin>>n;
    cin>>x>>y;
    for(int i=0;i<n-1;i++){
        int k;
        cin>>k;
        a[k][i+2]=1;
    }
    if(a[x][y]==1){
    	cout<<x;
    	return 0;
    }
    if(a[y][x]==1){
    	cout<<y;
    	return 0;
    }
    dfsx(x);
    dfsy(y);
    if(ans==0){
    	ans=1;
    }
    cout<<ans;


    return 0;
}