#include <cstdio>
#define N 100012
#include <vector>

using namespace std;
FILE *f,*g;

int firstp[N],nivel[N],rmq[20][2*N],log[N],n,nr;
vector <int> graph[N];
bool viz[N];

void RMQ()
{
    for(int i=2;i<=nr;++i)
        log[i]=1+log[i/2];
    int p=1;
    for(int i=1;i<=log[nr];++i)
    {
        for(int j=1;j+p<=nr;++j)
        {
            if(nivel[rmq[i-1][j]]<=nivel[rmq[i-1][j+p]])
                rmq[i][j]=rmq[i-1][j];
            else
                rmq[i][j]=rmq[i-1][j+p];
        }
        p*=2;
    }
}
void euler(int nod)
{
    viz[nod]=1;
    rmq[0][++nr]=nod;
    firstp[nod]=nr;
    for(int i=0;i<graph[nod].size();++i)
        if(!viz[graph[nod][i]])
            nivel[graph[nod][i]]=nivel[nod]+1,euler(graph[nod][i]),rmq[0][++nr]=nod;

}
int main()
{
    f=fopen("lca.in","r");
    g=fopen("lca.out","w");
    int m,x;
    fscanf(f,"%d %d",&n,&m);
    for(int i=1;i<n;++i)
    {
        fscanf(f,"%d",&x);
        graph[x].push_back(i+1);
    }
    euler(1);
    RMQ();
    int a,b,dif,lin,p,sol;
    for(int i=1;i<=m;++i)
    {
        fscanf(f,"%d %d",&a,&b);
        a=firstp[a];
        b=firstp[b];
        dif=b-a+1;
        lin=log[dif];
        p=(1<<lin);
        sol=min(rmq[lin][a],rmq[lin][b-p+1]);
        fprintf(g,"%d\n",sol);
    }
    fclose(f);
    fclose(g);
    return 0;
}