#include <bits/stdc++.h>

using namespace std;
ifstream f("lca.in");
ofstream g("lca.out");
//----------------------------
//Variabile globale
vector<int>v[800001];
int nr,ap[800001];
pair<int,int>rmq[800001][21];
//----------------------------
//Functii
void citeste();
void dfs(int,int);
void calculeaza_rmq();
//----------------------------
int main()
{
	citeste();
	return 0;
}
//----------------------------
void calculeaza_rmq()
{
	int k=log2(nr);
	for(int j = 1; j <= k+1; ++j)
		for(int i = 1; i <= nr - (1 << j) + 1; ++i)
		{
		    int x = rmq[i][j - 1].first;
		    int y = rmq[i][j - 1].second;
		    int x2 = rmq[i + (1 << (j - 1))][j - 1].first;
		    int y2 = rmq[i + (1 << (j - 1))][j - 1].second;
		    if(x<x2)
                rmq[i][j] = {x,y};
            else rmq[i][j] = {x2,y2};
		}
}
//---------------------------
void dfs(int nod,int grad)
{
	rmq[++nr][0].first = grad;
	rmq[nr][0].second = nod;
	if(v[nod].size()==0)
	{
		return;
	}
	for(int i = 0; i < v[nod].size(); ++i)
		if(!ap[v[nod][i]])
		{
			ap[v[nod][i]] = nr + 1;
			dfs(v[nod][i],grad + 1);
			rmq[++nr][0].first = grad;
			rmq[nr][0].second = nod;
		}
}
//---------------------------
void citeste()
{
	int n,m;
	f >> n >> m;
	for(int i = 2; i <= n; ++i)
	{
		int a;
		f >> a;
		v[a].push_back(i);
	}
	ap[1] = 1;
	dfs(1,0);
	calculeaza_rmq();
	while(m--)
	{
		int st,dr;
		f >> st >> dr;
		st = ap[st];
		dr = ap[dr];
		if(st > dr)
            swap(st,dr);
		int k = log2(dr - st + 1);
		int x = rmq[st][k].first;
		int y = rmq[st][k].second;
		int x2 = rmq[dr - (1 << k) + 1][k].first;
		int y2 = rmq[dr - (1 << k) + 1][k].second;
		if(x<x2)
            g << y << '\n';
        else g << y2 << '\n';
	}
}