#include<fstream>
#include<vector>
using namespace std;

int i,j,n,m,x,st,dr,d[400010],nr=0,prim[400010],arb[600010],sol;
vector<int> a[100010];
inline void euler(int nod)
{
	int i;
	d[++nr]=nod;
	prim[nod]=nr;
	for(int i=0;i<a[nod].size();++i)
	{
		euler(a[nod][i]);
		d[++nr]=nod;
	}
}
inline void adauga(int nod,int st,int dr,int poz,int val)
{
	int mij;
	if(st==dr)
		arb[nod]=val;
	else
	{
		mij=(st+dr)/2;
		if(poz<=mij)
			adauga(nod*2,st,mij,poz,val);
		else
			adauga(nod*2+1,mij+1,dr,poz,val);
		arb[nod]=min(arb[nod*2],arb[nod*2+1]);
	}
}
inline void det(int nod,int st,int dr,int a,int b)
{
	int mij;
	if(a<=st&&dr<=b)
	{
		if(arb[nod]<sol)
			sol=arb[nod];
		return ;
	}
	else
	{
		mij=(st+dr)/2;
		if(a<=mij)
			det(nod*2,st,mij,a,b);
		if(mij<b)
			det(nod*2+1,mij+1,dr,a,b);
	}
}
int main()
{
	FILE *f=fopen("lca.in","r");
	FILE *g=fopen("lca.out","w");
	fscanf(f,"%d%d",&n,&m);
	for(i=1;i<n;++i)
	{
		fscanf(f,"%d",&x);
		a[x].push_back(i+1);
	}
	euler(1);
	for(i=1;i<=nr;++i)
		adauga(1,1,nr,i,d[i]);
	for(i=1;i<=m;++i)
	{
		fscanf(f,"%d%d",&st,&dr);
		sol=1<<30;
		if(prim[st]<=prim[dr])
		det(1,1,nr,prim[st],prim[dr]);
		else
			det(1,1,nr,prim[dr],prim[st]);
	fprintf(g,"%d\n",sol);
	}
	return 0;
}