#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
#define Nmax 100005
#define pb push_back
using namespace std;

ifstream fin("lca.in");
ofstream fout("lca.out");
int k, ans[Nmax * 4], poz[Nmax], g[Nmax], ad[Nmax], x, lg2[4 * Nmax], n, m, y, q;
int rmq[20][4 * Nmax], rmqp[20][4 * Nmax], fol[4 * Nmax];
vector<pair<int,int> >v[Nmax];
vector<int>fii[Nmax];
stack<int>st;

void lca()
{
    st.push(1);
    while(!st.empty())
    {
        int nod = st.top();
        if(g[nod] == 0)
        {
            ans[++k] = nod;
            poz[nod] = k;
            st.pop();
        }
        else
        {
            int j = v[nod].size() - 1;
            while(fol[v[nod][j].second] == 1)
            {
                v[nod].pop_back();
                j--;
            }
            int vecin = v[nod][j].first;
            g[nod]--;
            g[vecin]--;
            fol[v[nod][j].second] = 1;
            v[nod].pop_back();
            st.push(vecin);
        }
    }
}
void dfs(int nod)
{
    for(int i = 0 ; i < fii[nod].size(); i++)
    {
        int fiu = fii[nod][i];
        ad[fiu] = ad[nod] + 1;
        dfs(fiu);
    }
}
int main()
{
    fin >> n >> m;
    for(int i = 1; i < n; i++)
    {
        fin >> x;
        fii[x].pb(i + 1);
        for(int j = 1; j <= 2; j++)
        {
            v[x].pb({i + 1, ++q});
            v[i + 1].pb({x, q});
            g[x]++;
            g[i + 1]++;
        }

    }
    ad[1] = 1;
    dfs(1);
    lca();
    //for(int i = 1; i <= k; i++)fout << poz[ans[i]] <<" " ;
    lg2[1] = 0;
    for(int i = 2; i <= k; i++)
        lg2[i] = lg2[i / 2] + 1;
    for(int i = 1; i <= k; i++)
    {
        rmq[0][i] = ad[ans[i]];
        rmqp[0][i] = ans[i];
    }
    for(int i = 1 ; i <= lg2[k]; i++)
        for(int j = 1; j <= k - (1 << i) + 1; j++)
        {
            if(rmq[i - 1][j] < rmq[i - 1][j + (1 << (i - 1))])
            {
                rmq[i][j] = rmq[i - 1][j];
                rmqp[i][j] = rmqp[i - 1][j];
            }
            else
            {
                rmq[i][j] = rmq[i - 1][j + (1 << (i - 1))];
                rmqp[i][j] = rmqp[i - 1][j + (1 << (i - 1))];
            }
           // fout << rmq[i][j] << ";" << rmqp[i][j] <<" " ;
        }
    for(int i = 1; i <= m; i++)
    {
        fin >> x >> y;
        if(poz[x] > poz[y])swap(x,y);
        int l = lg2[poz[y] - poz[x] + 1];
        if(rmq[l][poz[x]] < rmq[l][poz[y] - (1 << l) + 1])
            fout << rmqp[l][poz[x]];
        else fout << rmqp[l][poz[y] - (1 << l) + 1];
        fout << '\n';
    }
    return 0;
}