#include<stdio.h>

#define Nmax 100010
#define Nlog 20

struct nod
{
    int info;
    nod *urm;
} *l[Nmax];

int n,m,t[Nmax];
int E[ Nmax<<1 ],nt,L[ Nmax<<1 ],First[Nmax];
int Rmq[Nmax << 2][Nlog],lg[Nmax << 2];

void cit();
void solve();
void add(nod*&,int);
void df(int,int);
void rmq();
void debug();
int min(int,int);

int main()
{
    cit();
    
    df(1,0);
    
    rmq();
    
  //  debug();
    
    solve();
    
    return 0;
}

void solve()
{
    int a,b,dif,misc,k,sol;
    for(; m ;--m)
        {
        scanf("%d%d",&a,&b);
        a=First[a];
        b=First[b];
        if (a>b) 
            {misc=a; a=b; b=misc;}
            
        dif=b-a+1;
        k=lg[dif];
        misc=dif - (1<<k);
        sol=Rmq[a][k];
        if (L[sol] > L[ Rmq[a+misc][k] ])
            sol=Rmq[a+misc][k];
            
        printf("%d\n",E[sol]);
        }
}

void rmq()
{
    for(int i=2;i<=nt;++i)
        lg[i]=lg[i>>1]+1;
    for(int i=1;i<=nt;++i)
        Rmq[i][0]=i;
        
    for(int i=1; (1<<i)<=nt ; ++i)
        for(int j=1 , p=(1<<(i-1)); j+(1<<i)-1<=nt ;++j)
            {
            Rmq[j][i]=Rmq[j][i-1];
            if (L[ Rmq[j][i] ] > L[ Rmq[j+p][i-1] ])
                Rmq[j][i]= Rmq[j+p][i-1];
            }
}

void df(int k,int niv)
{
    E[++nt]=k;
    L[nt]=niv;
    First[k]=nt;
    
    for(nod *t=l[k] ; t ; t=t->urm)
        {
        df(t->info , niv+1);
        
        E[++nt]=k;
        L[nt]=niv;
        }
}

void cit()
{
    freopen("lca.in","r",stdin);
    freopen("lca.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(int i=2;i<=n;++i)
        {
        scanf("%d",&t[i]);
        add(l[t[i]],i);
        }
}

void add(nod *&inc,int info)
{
    nod *p=new nod;
    p->info=info;
    p->urm=inc;
    inc=p;
}

int min(int i,int j)
{
    if (i>j)
        return j;
    return i;
}

void debug()
{
    printf("E: ");
    for(int i=1;i<=nt;++i)
        printf("%d ",E[i]);
    printf("\n");
    
    printf("L: ");
    for(int i=1;i<=nt;++i)
        printf("%d ",L[i]);
    printf("\n");
    
    printf("First: ");
    for(int i=1;i<=n;++i)
        printf("%d ",First[i]);
    printf("\n");
    
    
    printf("\n");
    printf("\n");
    for(int i=0;i<=4;++i)
        {
        for(int j=1;j<=nt;++j)
            printf("%d ",Rmq[j][i]);
        printf("\n");
        }
    printf("\n");
    printf("\n");
}