#include <fstream>
#include <bitset>
#include <cmath>
#include <map>
#define F first
#define S second
#define Max 100001

using namespace std;

ifstream cin("lca.in");
ofstream cout("lca.out");

int n,m,base;
int vf[200001],urm[200001],last[100001],nr;
pair<int,int> eul[200001];
int nr2;
int interv[100001];

map <pair <int,int> ,int> value;

void adauga(int from,int to)
{
    vf[++nr]=to;
    urm[nr]=last[from];
    last[from]=nr;
}

void eul_dfs(int nod,int no,int niv=0)
{
    eul[++nr2].F=nod;
    eul[nr2].S=niv;

    interv[nod]=nr2;

    for(int nod2=last[nod];nod2;nod2=urm[nod2])
        if(vf[nod2]!=no)
        {
            eul_dfs(vf[nod2],nod,niv+1);

            eul[++nr2].F=nod;
            eul[nr2].S=niv;

            interv[nod]=nr2;
        }
}

int main()
{
    cin>>n>>m;

    for(int tat,i=2;i<=n;i++)
    {
        cin>>tat;

        adauga(tat,i);
        adauga(i,tat);
    }

    eul_dfs(1,0);

    for(int i=1;i<=2*n-1;i++)
        value[{i,i}]=i;

    for(int k=2;k<=2*n-1;k*=2)
        for(int i=1;i<=2*n-k;i++)
        {
            int p1=value[{i,i+k/2-1}],p2=value[{i+k/2,i+k-1}];

            if(eul[p1].S<eul[p2].S)
                value[{i,i+k-1}]=p1;
            else
                value[{i,i+k-1}]=p2;
        }

    for(int i,j,k=1;k<=m;k++)
    {
        cin>>i>>j;

        int a=interv[i],b=interv[j];
        if(a>b)
            swap(a,b);

        int m=pow(2,(int)log2(b-a+1));
        int sol;

        if( eul[ value[{a,a+m-1}] ].S<eul[ value[{b-m+1,b}] ].S)
            sol=value[{a,a+m-1}];
        else
            sol=value[{b-m+1,b}];

        cout<<eul[sol].F<<'\n';
    }
}