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

#define NMax 100005
#define LGMax 18

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

int n,m,lgn,N;
vector<int> v[NMax];
bool viz[NMax];
int gr[NMax],P[NMax];
int RMQ[NMax*2][LGMax];

void DFS(int s)
{
    viz[s]=1;
    for(int i=0;i<v[s].size();++i) if(!viz[v[s][i]])
    {
        gr[v[s][i]]=gr[s]+1;
        RMQ[++N][0]=s;
        DFS(v[s][i]);
    }
    RMQ[++N][0]=s;
    P[s]=N;
}

void build()
{
    int x;
    for(int aux=1;aux<=N;aux<<=1) lgn++;

    for(int j=1;j<=lgn;++j) for(int i=1;i<=N;++i)
    {
        x=i+(1<<(j-1));
        if(x>N) RMQ[i][j]=RMQ[i][j-1];
        else
        {
            if( gr[RMQ[i][j-1]] < gr[RMQ[x][j-1]] ) RMQ[i][j]=RMQ[i][j-1];
            else RMQ[i][j]=RMQ[x][j-1];
        }
    }
}

int main()
{
    int i,a,b,p,aux;

    f>>n>>m;
    for(i=2;i<=n;++i)
    {
        f>>a;
        v[a].push_back(i);
    }

    DFS(1);
    build();

    while(m--)
    {
        f>>a>>b;
        a=P[a], b=P[b];
        if(a>b) swap(a,b);

        for(p=-1,aux=1;aux<=b-a+1;aux<<=1) p++;
        if( gr[RMQ[a][p]] < gr[RMQ[b-(1<<p)+1][p]] ) g<<RMQ[a][p]<<"\n";
        else g<<RMQ[b-(1<<p)+1][p]<<"\n";
    }

    f.close();
    g.close();
    return 0;
}