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 en "\n"
#define dbg cout<<"rony\n"
 
#define MAXN 200010
#define inf 1e6+5
const ll mod = 1e9 + 7;
 
int n, q;
int up[MAXN][20];
 
void solve()
{
    cin >> n >> q;
    for (int i = 2; i <= n; i++) {
        cin >> up[i][0];
    }
 
    for (int log = 1; log < 20; log++)
    {
        for (int i = 1; i <= n; i++) {
            int ancestor = up[i][log - 1];
            up[i][log] = up[ancestor][log - 1];
        }
    }
 
    while (q--)
    {
        int v, k;
        cin >> v >> k;
        for (int log = 19; log >= 0; log--)
        {
            if (k >= (1 << log)) {
                k -= (1 << log);
                v = up[v][log];
            }
        }
        if (v == 0) cout << -1 << en;
        else cout << v << en;
    }
 
}
int main()
{
    IOS;
    ll t;
    t = 1;
 
    // cin >> t;
 
    int c = 0;
    while ( t-- )
    {
        // cout<<"Case "<<++c<<": ";
        solve();
    }
    return 0;
}