#include<stdio.h>
using namespace std;
const int N = 100005;
int vf[2 * N], lst[N], urm[2 * N], nr, n, m, ap[N];
bool viz[N];
const int PUTERE = 17, INF = 1 << 19;
int puteri[2 * N];
struct ptLCA
{
    int adanc, euler;
};
ptLCA v[2 * N], rmq[PUTERE + 2][2 * N];
void adauga (int x, int y)
{
    vf[++nr] = y;
    urm[nr] = lst[x];
    lst[x] = nr;
}
void dfs (int x, int adancime)
{
    int y, p;
    if (viz[x] == false)
    {
        ap[x] = ++nr;
        viz[x] = true;
    }
    v[nr].euler = x;
    v[nr].adanc = adancime;
    p = lst[x];
    while (p != 0)
    {
        y = vf[p];
        if (viz[y] == false)
        {
            dfs (y, adancime + 1);
            v[++nr].euler = x;
            v[nr].adanc = adancime;
        }
        p = urm[p];
    }
}
ptLCA minim (ptLCA a, ptLCA b)
{
    if (a.adanc < b.adanc)
        return a;
    return b;
}
void construieste ()
{
    int i, p = 1, j;
    for (i = 1; i <= 2 * n - 1; i++)
    {
        rmq[0][i].adanc = v[i].adanc;
        rmq[0][i].euler = v[i].euler;
    }
    for (i = 1; i <= PUTERE; i++)
    {
        for (j = 1; j <= 2 * n - 1; j++)
        {
            if (j + p <=  2 * n - 1)
                rmq[i][j] = minim (rmq[i - 1][j], rmq[i - 1][j + p]);
        }
        p <<= 1;
    }
    p = 1;
    for (i = 0; i <= PUTERE; i++)
    {
        puteri[p] = i;
        p <<= 1;
    }
}
int interog (int a, int b)
{
    int p, val, dif;
    ptLCA sol;
    sol.adanc = INF;
    while (a <= b)
    {
        dif = b - a + 1;
        val = dif & (-dif);
        p = puteri[val];
        sol = minim (sol, rmq[p][a]);
        a += val;
    }
    return sol.euler;
}

int main ()
{
    FILE *in, *out;
    in = fopen ("lca.in", "r");
    out = fopen ("lca.out", "w");
    fscanf (in, "%d%d", &n, &m);
    int i, x;
    for (i = 1; i <= n - 1; i++)
    {
        fscanf (in, "%d", &x);
        adauga (x, i + 1);
        adauga (i + 1, x);
    }
    nr = 0;
    dfs (1, 0);
    construieste();
    int j;
    int y, pozY, pozX;
    for (i = 1; i <= m; i++)
    {
        fscanf (in, "%d%d", &x, &y);
        pozY = ap[x];
        pozX = ap[y];
        if (pozX < pozY)
            fprintf (out, "%d\n", interog (pozX, pozY));
        else
            fprintf (out, "%d\n", interog (pozY, pozX));
    }
    return 0;
}