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

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

const int nmax = 1e5;
vector<int>g[nmax + 1];
vector<int>v;
int poz[nmax + 1];
int nivel[nmax + 1];
int dp[18][2*nmax + 1];
int pozi = 0;

void dfs(int node,int level)
{
    nivel[node] = level;
    level++;
    v.push_back(node);
    pozi++;
    poz[node] = pozi;


    for(int i = 0; i < g[node].size(); i++)
    {
        int vecin = g[node][i];
        if(nivel[vecin] == 0)
        {
             dfs(vecin,level);
             pozi++;
        }
        v.push_back(node);
        poz[node] = pozi;
    }
}
void build_rmq()
{
    for(int i = 0; i < v.size(); i++)
        dp[0][i] = v[i];

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

    for(int i = 1; i <= l2; i++)
        for(int j = 1; j <= length; 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 pozx = poz[x] - 1;
    int pozy = poz[y] - 1;
    if(pozx > pozy)
        swap(pozx, pozy);
    int length = pozy - pozx + 1;
    int exp = log2(length);
    int lint1 = (1<<exp);

    int cmp = dp[exp][pozx];
    int cmp2 = dp[exp][pozy - lint1 + 1];
    int finali = 0x3f3f3f3f;

    if(nivel[cmp] < finali)
        finali = cmp;
    if(nivel[cmp2] < nivel[finali])
        finali = cmp2;
    out<<finali<<'\n';
}
int main()
{
    int n,m;
    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;
}