#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
#include <queue>
#include <stack>
#include <cstring>

using namespace std;

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

const int DIM = 100005;

int n,m,x,root=1,viz[DIM],H[DIM],Min[DIM],y,p,a,b;

vector <int> G[DIM],S;
stack <int> Stack;

struct Graph
{
    int val,nod;
}rmq[20][DIM*3+5];

int lg[DIM*3+5];

void Read()
{
    fin>>n>>m;
    for(int i=1;i<n;i++)
    {
        fin>>x;
        G[x].push_back(i+1);
        G[i+1].push_back(x);
    }
}

void Euler()
{
    Stack.push(root);
    viz[root]=1;
    H[root]=1;
    int nr=0;
    p=-1;
    for(int i=1;i<=n;i++)
        Min[i]=-1;
    while(!Stack.empty())
    {
        int CrtNode=Stack.top();
        S.push_back(CrtNode);
        if(Min[CrtNode]<0)
            Min[CrtNode]=nr;
        nr++;
        p++;
        bool ok=false;
        vector <int> ::iterator it;
        for(it=G[CrtNode].begin();it!=G[CrtNode].end();it++)
        {
            if(!viz[*it])
            {
                viz[*it]=1;
                if(!H[*it])
                    H[*it]=H[CrtNode]+1;
                Stack.push(*it);
                ok=true;
                break;
            }
        }
        if(!ok)
            Stack.pop();
    }
}

void GetPos(int NodeX, int NodeY, int &x, int &y)
{
    if(Min[NodeX]<Min[NodeY])
        {
            x=Min[NodeX];
            y=Min[NodeY];
        }
    else
        {
            x=Min[NodeY];
            y=Min[NodeX];
        }
}

void RMQ()
{
    lg[1]=0;
    for(int i=2;i<=p;i++)
        lg[i]=lg[i/2]+1;
    for(int i=0;i<=p;i++)
    {
        rmq[0][i].val=H[S[i]];
        rmq[0][i].nod=S[i];
    }
    for(int i=1;(1<<i)<=p;i++)
    {
        for(int j=0;j<=p-(1<<i)+1;j++)
        {
            int l=(1<<(i-1));
            if(rmq[i-1][j].val<rmq[i-1][j+l].val)
            {
                rmq[i][j].val=rmq[i-1][j].val;
                rmq[i][j].nod=rmq[i-1][j].nod;
            }
            else
            {
                rmq[i][j].val=rmq[i-1][j+l].val;
                rmq[i][j].nod=rmq[i-1][j+l].nod;
            }
        }
    }
}

int QueryRMQ(int x, int y)
{
    int diff=y-x+1;
    int l=lg[diff];
    int sh=diff-(1<<l);
    if(rmq[l][x].val<rmq[l][x+sh].val)
        return rmq[l][x].nod;
    return rmq[l][x+sh].nod;
}

void Query()
{
    while(m--)
    {
        fin>>a>>b;
        GetPos(a,b,x,y);
        fout<<QueryRMQ(x,y)<<'\n';
    }
}

int main()
{
    Read();
    Euler();
    RMQ();
    Query();
}