#include <bits/stdc++.h>
#define NMAX 100008

using namespace std;
ifstream fin ("lca.in");
ofstream fout ("lca.out");

int n, m, x, L, timer, level;
vector <int> G[NMAX];
int tin[NMAX], tout[NMAX], up[NMAX][20], lvl[NMAX], logg[NMAX];

void DFS(int nod, int tata, int level);
int LCA(int u, int v);
bool stramos(int u, int v);

int main()
{
    ios_base::sync_with_stdio(0); fin.tie(0);
    fin >> n >> m;
    logg[1] = 0;
    for (int i = 2; i <= n; i++)
    {
        logg[i] = logg[i/2] + 1;
        fin >> x;
        G[x].push_back(i);
    }
    L = logg[n];
    DFS(1, 0, 0);
    int u, v;
    for (int i = 1; i <= m; i++)
    {
        fin >> u >> v;
        fout << LCA(u, v) << '\n';
    }
    return 0;
}

void DFS(int nod, int tata, int level)
{
    tin[nod] = ++timer;
    lvl[nod] = level;
    up[nod][0] = tata;
    for (int i = 1; i <= L; i++)
        up[nod][i] = up[up[nod][i-1]][i-1];

    for (auto el : G[nod])
        DFS(el, nod, level+1);

    tout[nod] = ++timer;
}

bool stramos(int u, int v)
{
    if (u == 0)
        return 1;
    return (tin[u] <= tin[v] && tout[v] <= tout[u]);
}

int LCA(int u, int v)
{
    if (stramos(u, v))
        return u;
    if (stramos(v, u))
        return v;
    for (int i = logg[lvl[u]]; i >= 0; i--)
        if (!stramos(up[u][i], v))
            u = up[u][i];
    return up[u][0];
}