#include <fstream>
#include <vector>
#define DIM 100011
using namespace std;
ifstream f("lca.in");
ofstream g("lca.out");
int n,m,T[DIM],a[21][DIM],nr,F[DIM],p[DIM];
pair<int,int> E[2*DIM];

vector<int> L[DIM];
vector<int>::iterator it;

void dfs(int nod,int niv){
    E[++nr]=make_pair(nod,niv);
    if(!F[nod]) F[nod]=nr;
    for(register int i=0;i<L[nod].size();i++){
        dfs(L[nod][i],niv+1);
        E[++nr]=make_pair(nod,niv);
    }
}

int main(void){
    register int i,b,j,jv,x,y;

    f>>n>>m;
    for(i=2;i<=n;i++)
        f>>T[i], L[T[i]].push_back(i);
    dfs(1,1);

    a[0][1]=1;
    for(i=2;i<=nr;i++)   p[i]=1+p[i/2],a[0][i]=i;
    for(i=1;(1<<i)<=nr;i++){
        for(j=1;j<=nr;j++){
            a[i][j]=a[i-1][j];
            jv=(1<<(i-1))+j;
            if(jv<=nr && E[a[i-1][jv]].second<=E[a[i][j]].second)
                a[i][j]=a[i-1][jv];
        }
    }

    for(i=1;i<=m;i++){
        f>>x>>y;
        x=F[x],y=F[y];
        if(x>y) jv=x,x=y,y=jv;
        b=p[y-x+1];
        jv=y-(1<<b)+1;
        if(E[a[b][x]].second<=E[a[b][jv]].second)
            g<<E[a[b][x]].first;
        else g<<E[a[b][jv]].second;
        g<<"\n";
    }
    f.close();
    g.close();
    return 0;
}