#include <cstdio>
#include <vector>
#define nmax 100005
using namespace std;
FILE *f=fopen("lca.in","r"),*g=fopen("lca.out","w");
int niv[2*nmax],first[nmax],arb[4*nmax],a,b,n,euler[2*nmax],k;
vector <int> l[nmax];
void eul(int nod, int p)
{
    int i,j;
    euler[++k]=nod;
    niv[k]=p;
    if(!first[nod])
        first[nod]=k;
    for(i=0;i<l[nod].size();i++)
    {
        j=l[nod][i];
        eul(j,p+1);
        euler[++k]=nod;
        niv[k]=p;
    }
}
void update(int nod, int st, int dr)
{
    if(st==dr)
    {
        if(st<=2*n)
        arb[nod]=st;

        return;
    }
    int mij=(st+dr)/2;
    update(nod*2,st,mij);
    update(nod*2+1,mij+1,dr);
    if(niv[arb[nod*2]]<=niv[arb[nod*2+1]])
        arb[nod]=arb[nod*2];
    else
        arb[nod]=arb[nod*2+1];
}
int query(int nod, int st, int dr)
{
    if(a<=st&&dr<=b)
        return arb[nod];
    int mij=(st+dr)/2,q1=0,q2=0;
    if(a<=mij)
        q1=query(nod*2,st,mij);
    if(b>mij)
        q2=query(nod*2+1,mij+1,dr);
    if(niv[q1]<niv[q2])
        return q1;
    return q2;
}
int main()
{
    int i,j,m,x,y,p=1;
    fscanf(f,"%d %d",&n,&m);
    for(i=2;i<=n;i++)
    {
        fscanf(f,"%d",&x);
        l[x].push_back(i);
    }
    eul(1,1);
    while(p<2*n)
        p=p*2;
    niv[0]=2*nmax;
    update(1,1,p);
    for(i=1;i<=m;i++)
    {
        fscanf(f,"%d %d",&x,&y);
        a=first[x]; b=first[y];
        if(a>b)
        {
            a=a+b;
            b=a-b;
            a=a-b;
        }
        fprintf(g,"%d\n",euler[query(1,1,p)]);
    }
    fclose(f);
    fclose(g);
    return 0;
}