#include <fstream>
#include <vector>
#include <cmath>
using namespace std;

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

int d[200005][20], euler[400005], poz[200005], h[200005], nr;
vector <int> v[200005];

void dfs(int nod)
{   int i;
    euler[++nr]=nod; // vectorul cu nodurile in parcurgerea Euler
    poz[nod]=nr;  // poz[nod] = pozitia primei apartii a nodului in parcurgerea Euler
    for(i=0; i<v[nod].size(); i++)
        if(h[v[nod][i]]==0)
        {
            h[v[nod][i]]=h[nod]+1; // nivelul nodului curent
            dfs(v[nod][i]);
            euler[++nr]=nod;
        }
 }

int main()
{
    int n, m, t, i, j, aux, x, y, p, a;
    f >> n >> m;
    for(i=2; i<=n; i++)
    {
        f >> t;
        v[t].push_back(i);
    }

    dfs(1);

    //RMQ - pentru determinatea nodurilor de pe nivelul minim
    // in parcurgerea Euler
    for(i=1; i<=nr; i++) d[i][0]=euler[i];

    for(j=1;(1<<j)<=nr;j++)
      for(i=1;i+(1<<j)-1<=nr;i++)
        if(h[d[i][j-1]]<h[d[i+(1<<(j-1))][j-1]]) d[i][j]=d[i][j-1];
        else d[i][j]=d[i+(1<<(j-1))][j-1];

    for(i=1; i<=m; i++)
    {
        f >> x >> y;
        x=poz[x];  y=poz[y];
        if(x>y) swap(x,y);
        p=log2(y-x+1);
        if (h[d[x][p]] < h[d[y-(1<<p)+1][p]]) a = d[x][p];
        else a = d[y-(1<<p)+1][p];
        g<<a<<'\n';
    }

    return 0;
}