#include <fstream>
#include <vector>
#include <utility>
#define MX 100001
#define minim(a,b) ((a<b) ? a : b)
using namespace std;

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

int n,m;
vector<int> c[MX];
vector<int> eul;
int niv[MX], ap[MX];
int nr1,nr2;

int r[6*MX],l;

void citire()
{
    int i,x;
    fin>>n>>m;
    for(i=2; i<=n; i++)
    {
        fin>>x;
        c[x].push_back(i);
    }
}

void repr_euler(int p)
{
    vector<int>::iterator it;
    eul.push_back(p);

    if(ap[p] == 0)
    {
        ap[p] = eul.size()-1;
    }

    for(it=c[p].begin(); it!=c[p].end(); it++)
    {
        repr_euler(*it);
        eul.push_back(p);
    }
}

void nivel(int p)
{
    vector<int>::iterator it;
    for(it=c[p].begin(); it!=c[p].end(); it++)
    {
        niv[*it] = niv[p]+1;
        nivel(*it);
    }
}

inline int query(int nod, int left, int right)
{
    if(nr1<=left && right<=nr2)
    {
        return r[nod];
    }

    /*fout<<left<<' '<<right<<'\n';
    fout.flush();*/

    int mid = (left+right)>>1;
    int s,d;
    s=d=2000000;
    if(nr1 <= mid)
    {
        s = query(nod<<1, left, mid);
    }
    if(mid < nr2)
    {
        d = query((nod<<1)+1, mid+1, right);
    }

    return minim(s, d);
}

inline void adauga(int nod, int left, int right)
{
    if(left == right)
    {
        r[nod] = nr1;
        return;
    }
    int mid = (left+right)>>1;
    if(nr2 <= mid) adauga(nod<<1, left, mid);
    else adauga((nod<<1)+1, mid+1, right);

    r[nod] = minim(r[nod<<1], r[(nod<<1)+1]);
}

int main()
{
    citire();
    eul.push_back(0);
    repr_euler(1);
    nivel(1);

    int i;
    l = eul.size()-1;
    for(i=1; i<=l; i++)
    {
        nr1 = eul[i];
        nr2 = i;
        adauga(1, 1, l);
    }

    for(i=1; i<=m; i++)
    {
        fin>>nr1>>nr2;
        if(ap[nr1] > ap[nr2]) swap(nr1, nr2);
        nr1 = ap[nr1];
        nr2 = ap[nr2];

        fout<<query(1, 1, l)<<'\n';
    }


    fin.close(); fout.close();
    return 0;
}