#include<fstream>
#include<vector>
#define dim 100007

using namespace std;


ifstream f("lca.in");
ofstream g("lca.out");
int rmq[20][dim];
int viz[dim],eul[3*dim],po[dim],q[dim],x;
int k,n,m,i,j,a,b,H;
vector<int>G[dim];
void dfs(int nod){
	viz[nod]=1;
	eul[++k]=nod;
	q[nod]=k;
	for(int i=0;i<G[nod].size();++i)
		if(viz[G[nod][i]]==0){
			viz[G[nod][i]]=1;
			dfs(G[nod][i]);
			eul[++k]=nod;
		}
}
int main () {
	
	f>>n>>m;
	
	for(i=1;i<n;++i){
		f>>x;
		G[x].push_back(i+1);
	}
	//parcurgere euler
	dfs(1);
	//rmq
	for(i=2;i<=dim;++i)
		po[i]=po[i/2]+1;
	
	for(i=1;i<=k;++i)
		rmq[0][i]=eul[i];
	
	for(i=1;(1<<i)<=k;++i) {
		
		for(j=1;j+(1<<i)-1<=k;++j)
			rmq[i][j]=min(rmq[i-1][j],rmq[i-1][j+(1<<(i-1))]);
		
	}
	
	for(i=1;i<=m;++i){
		f>>a>>b;
		a=q[a];b=q[b];
		
		if(a>b)
			swap(a,b);
		H=po[b-a+1];
		g<<min(rmq[H][a],rmq[H][b+1-(1<<H)])<<"\n";
	}
	return 0;
}