#include <iostream>
#include <fstream>
#include <climits>
#include <vector>

using namespace std;

ifstream in("lca.in");
ofstream out("lca.out");

const int NMAX = 1e5;
const int LOGMAX = 18;

int n, m, c;

int poz[1 + 2 * NMAX];
int depth[1 + 2 * NMAX];

int vec[1 + 2 * NMAX];
int dp[1 + 3 * NMAX][1 + LOGMAX];

vector < int > g[1 + NMAX];

void dfs(int i, int d)
{
    int j = 0;
    int sz = g[i].size();
    while(j < sz)
    {
        dfs(g[i][j], d + 1);
        poz[++c] = i;
        vec[i] = c;
        depth[c] = d;
        j++;
    }

    poz[++c] = i;

    vec[i] = c;
    depth[c] = d;
}

void rmq()
{
    for(int i = 0; i <= 3 * NMAX; i++)
    {
        for(int j = 0; j <= LOGMAX; j++)
        {
            dp[i][j] = INT_MAX;
        }
    }

    for(int i = 1; i <= c; i++)
    {
        dp[i][0] = poz[i];
    }

    for(int j = 1; (1 << j) <= c; j++)
    {
        for(int i = 1; i <= c; i++)
        {
            dp[i][j] = min(dp[i][j - 1], dp[i + (1 << (j - 1))][j - 1]);
        }
    }
}


void dca()
{
    for(int i = 1; i <= m; i++)
    {
        int x, y, delta;

        in >> x >> y;

        x = vec[x];
        y = vec[y];

        if(y < x)
            swap(x, y);

        delta = y - x;

        if(delta == 0)
        {
            out << dp[x][0] << '\n';
        } else {
            int k = 0;
            for(k; (1 << k) <= delta; k++);
            k--;
            out << min(dp[x][k], dp[y - (1 << k) + 1][k]) << '\n';
        }
    }
}

int main()
{
    in >> n >> m;

    for(int i = 2; i <= n; i++)
    {
        int x;

        in >> x;
        g[x].push_back(i);
    }

    dfs(1, 1);

    rmq();
    dca();

    in.close();
    out.close();

    return 0;
}