#include <iostream>
#include <fstream>
using namespace std;
ifstream f("lca.in");
ofstream g("lca.out");
int n, v[200000], m, nivel[200000], e[400500], j=1, nr1, nr;
int rmq[50][200000],lg[200000];
void citire()
{
    f>>n>>m;
    int i;v[0]=1;
    for(i=1;i<n;i++)
    {
        f>>v[i];
        if(v[i]==1) nr1++;
    }
}
void niv (int nod)
{
    if(nod==1 && v[nod]==1)  nivel[nod]=0;
    else
        nivel[nod]=nivel[v[nod-1]]+1;
}
int gasit (int x)
{
    for(int i=1;i<=n;i++)
        if(v[i]==x) return 1;
    return 0;
}
void euler (int x)
{
    int i;
    if(x==1)    nr++;
    if(nr<=nr1+1)
    {   e[j]=x;
        j++;
        if(gasit(x))
            for(i=x+1;i<=n;i++)
            {
                if(v[i-1]==x)
                    euler(i);
            }
        else
            v[x-1]=-v[x-1], euler(-v[x-1]);
    }
}
void rmq1 (int N[])
{
    int i, k, l;
    for (i=2;i<=j;i++)
        lg[i]=lg[i/2]+1;
    for (i=1;i<=j;i++)
        rmq[0][i]=N[i];
    for (i=1;(1<<i)<=j;i++)
       for (k=1;k<=j-(1<<i)+1;k++)
        {
            l=1<<(i-1);
            rmq[i][k]= min(rmq[i-1][k],rmq[i-1][k+l]);
        }
}
int prima (int a)
{
    for(int i=1;i<=j;i++)
        if(e[i]==a) return i;
    return -1;
}
int main()
{
    citire();
    int i, diff,l, sh ;
    cout<<n<<endl;
    for(i=1;i<=n;i++)
        niv(i);
    euler(1);
    j--;
    int N[j+1];
    for(i=1;i<=j;i++)
        N[i]=nivel[e[i]];
    rmq1(N);
    while(m--)
    {
        int x, y, mi, ok=0;
        f>>x>>y;
        x=prima(x); y=prima(y);
        if(x>y)
            x+=y, y=x-y, x=x-y;
        diff=y-x+1;
        l=lg[diff];
        sh=diff-(1<<l);
        mi=min(rmq[l][x],rmq[l][x+sh]);
        for(i=x;i<=y && ok==0;i++)
            if(N[i]==mi)
                ok=1, g<<e[i]<<"\n";
    }
    f.close();
    g.close();
}