#include <fstream>
#include <vector>
#include <map>

std::ifstream f("lca.in");
std::ofstream g("lca.out");

struct index_info {
    int node;
    int level;
};

int N, M, x, y, val, log_mem[200003], D[21][200003], pos_in_tour[200003];
std::vector<int> G[100003];
std::vector<index_info> euler_tour;

inline void preprocess_log()
{
    log_mem[0] = -1;
    for(int i = 1; i <= euler_tour.size() - 1; i++) {
        log_mem[i] = log_mem[i / 2] + 1;
        D[0][i] = i;
    }
}

void do_euler_tour(int nod = 1, int level = 1)
{
    if(!pos_in_tour[nod]) {
        euler_tour.push_back({nod, level});
        pos_in_tour[nod] = euler_tour.size() - 1;
        for(auto &val: G[nod]) {
            do_euler_tour(val, level + 1);
            euler_tour.push_back({nod, level});
        }
    }

}

int main()
{
    f >> N >> M;
    for(int i = 2; i <= N; i++) {
        f >> x;
        G[x].push_back(i);
    }
    euler_tour.push_back({0, 0});
    do_euler_tour();
    preprocess_log();
    for(int i = 1; i <= log_mem[euler_tour.size() - 1]; i++) {
        for(int j = 1; j <= euler_tour.size() - (1 << i); j++) {
            if(euler_tour[D[i - 1][j]].level < euler_tour[D[i - 1][j + (1 << i - 1)]].level)
                D[i][j] = D[i - 1][j];
            else
                D[i][j] = D[i - 1][j + (1 << i - 1)];
        }

    }
    for(int i = 1; i <= M; i++) {
        f >> x >> y;
        int x1 = pos_in_tour[x], x2 = pos_in_tour[y];
        if(x1 == x2)
            g << euler_tour[x1].node << "\n";
        else {
            if(x1 > x2) std::swap(x1, x2);
            int k = log_mem[x2 - x1];
            if(euler_tour[D[k][x1]].level < euler_tour[D[k][x2 - (1 << k) + 1]].level)
                g << euler_tour[D[k][x1]].node << "\n";
            else
                g << euler_tour[D[k][x2 - (1 << k) + 1]].node << "\n";
        }
    }
    return 0;
}