#include <bits/stdc++.h>
#define dim 100005
using namespace std;
ifstream fin("aib.in");
ofstream fout("aib.out");
int prim[dim],nivel[dim],niv,euler[2*dim],k,Log[dim],d[30][dim],n,m,i,x,y;
vector<int> L[dim];
int e(int nod)
{
    euler[++k]=nod;
    prim[nod]=k;
    nivel[nod]=niv;
    for(auto it:L[nod])
    {
        niv++;
        e(it);
        niv--;
        euler[++k]=it;
    }
}
int query(int st,int dr){
int l=dr-st+1;
int lg=Log[l];
int p1=d[lg][st];
int p2=d[lg][st+l-(1<<lg)];
if(nivel[p1]<nivel[p2])
                {
                return p1;
                    }
                else
                    return p2;
}
int main()
{
    fin>>n>>m;
    for(i=1; i<=n; i++)
    {
        int x;
        fin>>x;
        L[x].push_back(i);
    }
    niv=1;
    e(1);
    /// RMQ
    for(i=1; i<=n; i++)
        d[0][i]=i;
    int p=1;

        for(int lun=1; lun<=22; lun++)
        {
            p*=2;
            ///
            for(i=1; i<=n-lun+1; i++)
            {
                /// inceput secv
                int p1=d[lun-1][i];
                int p2=d[lun-1][i+lun];
                if(nivel[p1]<nivel[p2])
                {
                    d[lun][i]=p1;
                }
                else
                    d[lun][i]=p2;
            }
        }
    Log[1]=0;
    for(i=2; i<=k; i++)
        Log[i]=1+Log[i/2];
    for(i=1;i<=m;i++){
        fin>>x>>y;
        x=prim[x];
        y=prim[y];
        if(x>y)
            swap(x,y);
        fout<<query(x,y);
    }
}