#include <bits/stdc++.h>

using namespace std;
ifstream fin("lca.in");
ofstream fout("lca.out");
const int nmax = 1e5+2;
void dfs(int nod, int nivel);

int n, m, first[nmax], lg2[nmax], euler;
vector<bool> frunza(nmax, true);
vector<int> adj[nmax];
struct ura
{
    int nod, nivel;
    bool operator < (const ura& aux) const
    {
        return nivel < aux.nivel;
    }
} rmq[19][2*nmax];

int main()
{
    fin>>n>>m;
    for(int i = 2; i <= n; ++i)
    {
        int x;
        fin>>x;
        frunza[x] = false;
        adj[x].push_back(i);
        lg2[i] = lg2[i/2] + 1;
    }
    dfs(1, 0);

    for(int p = 1; p <= 18; ++p)
    {
        for(int i = 1; i <= euler; ++i)
        {
            rmq[p][i] = rmq[p-1][i];
            int j = i + (1<<(p-1));
            if(j <= euler)
                rmq[p][i] = min(rmq[p][i], rmq[p-1][j]);
        }
    }

    while(m--)
    {
        int x, y;
        fin>>x>>y;
        x = first[x];
        y = first[y];
        if(x > y)
            swap(x, y);
        int p = lg2[y - x + 1];
        ura ans = min(rmq[p][x], rmq[p][y - (1<<p) + 1]);
        fout<<ans.nod<<"\n";

    }
    return 0;
}

void dfs(int nod, int nivel)
{
    ++euler;
    rmq[0][euler].nivel = nivel;
    rmq[0][euler].nod = nod;
    if(!first[nod])
        first[nod] = euler;
    for(auto i : adj[nod])
    {
        dfs(i, nivel+1);
        ++euler;
        rmq[0][euler].nivel = nivel;
        rmq[0][euler].nod = nod;
    }
}