#include<fstream>
#include<vector>
#define lim 100002
using namespace std;
ifstream f("lca.in");
ofstream g("lca.out");
vector<int>G[lim];
int A[20][lim],n,l,i,j,m,a,x,y,Pr[lim],pr[lim],eul[2*lim];
int min(int a,int b){
	
	if(a<b)
		return a;
	return b;
}
void dfs(int nod){
	eul[++a]=nod;
	Pr[nod]=a;
	
	for(int i=0;i<G[nod].size();++i){
		dfs(G[nod][i]);
		eul[++a]=nod;
	}
	
}
int main (){
	f>>n>>m;
	for(i=2;i<=n;i++){
		f>>x;
		G[x].push_back(i);
	}
	dfs(1);
	for(i=2;i<=a;i++)
		pr[i]=pr[i/2]+1;
	for(i=1;i<=a;i++)
		A[0][i]=eul[i];
	for(i=1;(1<<i)<=a;i++){
		
		for(j=1;j+(1<<i)-1<=a;j++){
			
			A[i][j]=min(A[i-1][j],A[i-1][j+(1<<(i-1))]);
		}
	}
	
	for(i=1;i<=m;i++){
		f>>x>>y;
		x=Pr[x];
		y=Pr[y];
		l=pr[y-x+1];
		g<<min(A[l][x],A[l][y+1-(1<<l)])<<"\n";
	}
	
	return 0;
}