#include <fstream>
#include <vector>
#include <cmath>

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

const int nmax = 100000;

vector<int>g[nmax + 1];
int nivel[nmax + 1];
int poz[nmax + 1];
int dp[18][2 * nmax + 1];
vector<int>v;
int n,m;
int var = 0;

void dfs(int node, int lvl)
{
    v.push_back(node);

    var++;
    poz[node] = var;

    nivel[node] = lvl;
    lvl++;


    for(int i = 0; i < g[node].size(); i++)
    {
        if(nivel[g[node][i]] == 0)
        {
            dfs(g[node][i],lvl);
            var++;
        }

        v.push_back(node);
        poz[node] = var;
    }
}
void build_rmq()
{
    for(int i = 0; i < v.size(); i++)
        dp[0][i] = v[i];

    int l = log2(v.size());
    int l2 = v.size();

    for(int i = 1; i <= l; i++)
        for(int j = 1; j <= l2; j++)
        {
            if(nivel[dp[i - 1][j]] < nivel[dp[i - 1][j + (1<<(i - 1))]])
                dp[i][j] = dp[i - 1][j];
            else
                dp[i][j] = dp[i - 1][j + (1<<(i - 1))];
        }
}
void find_ancestor(int x, int y)
{
    int lastx = poz[x] - 1;
    int lasty = poz[y] - 1;
    if(lastx > lasty)
        swap(lastx, lasty);

    int length = lasty - lastx + 1;
    int exp = log2(length);
    int lint1 = (1<<exp);

    int cmp = dp[exp][lastx];
    int cmp2 = dp[exp][lasty - lint1 + 1];
    int finali = 1e9;

    if(nivel[cmp] < finali)
        finali = cmp;
    if(nivel[cmp2] < finali)
        finali = cmp2;

    out<<finali<<'\n';
}
int main()
{
    in>>n>>m;
    for(int i = 1; i <= n - 1; i++)
    {
        int x;
        in>>x;
        g[x].push_back(i + 1);
    }
    dfs(1,1);

    build_rmq();
    for(int i = 1; i <= m ; i++)
    {
        int x,y;
        in>>x>>y;
        find_ancestor(x,y);
    }

    return 0;
}