#include <fstream>
#include <vector>
#include <cmath>
using namespace std;
ifstream cin("lca.in");
ofstream cout("lca.out");

int n, m, dad, mn[20][200001],pmin[200001], pmax[200001];
bool viz[100100];
vector <int> sn[100001];
vector <pair<int,int> > eul;

void dfs(int x,int dpth);
void rmq();
int main()
{
    cin>>n>>m;
    for(int i=2; i<=n; ++i)
    {
        cin>>dad;
        sn[dad].push_back(i);
    }

    eul.push_back({0,0});
    dfs(1,0);///
    rmq();
    for(int i=1; i<eul.size(); ++i)
        if(!pmin[eul[i].first])
            pmin[eul[i].first]=i;

    int lft, rght, lg, l2, p2,x,y;
    for(int i=1; i<=m; ++i)
    {
        cin>>lft>>rght;
        x=pmin[lft];
        y=pmin[rght];
        if(x>y)
            swap(x,y);
        lg=y-x+1;
        p2=log2(lg);
        l2=pow(2,p2);
        cout<<min(mn[p2][y],mn[p2][x+l2-1])<<'\n';
    }
/**/
    return 0;
}

void dfs(int x,int dpth)
{
    eul.push_back({x,dpth});
    viz[x]=1;
    for(int i=0; i<sn[x].size(); ++i)
        if(!viz[sn[x][i]])
        {
            dfs(sn[x][i],dpth+1);
            eul.push_back({x,dpth});
        }
}

void rmq()
{
    for(int i=1; i<eul.size(); ++i)
        mn[0][i]=eul[i].first;
    for(int p=2, exp=1; p<eul.size(); p*=2, ++exp)
        for(int ind=p; ind<eul.size(); ++ind)
            mn[exp][ind]=min(mn[exp-1][ind],mn[exp-1][ind-(p/2)]);
}