#include <stdio.h>
#include <stdlib.h>

int eul[200002], lst[100001], urm[100001], f[100001], y, poz[100001], r[200002][16], logg[100001];

int minim(int a, int b){
    if(a<b)
        return a;
    return b;
}

int intreb(int a, int b){
    if(a>b){
        b=a+b;
        a=b-a;
        b=b-a;
    }
    int l=logg[b-a+1];
    return minim(r[a+(1<<l)-1][l], r[b][l]);
}

void euller(int nr){
    int p=lst[nr], nr2;
    eul[++y]=nr;
    poz[nr]=y;
    while(p!=0){
        nr2=f[p];
        euller(nr2);
        eul[++y]=nr;
        p=urm[p];
    }
}

int main(){
    FILE *fin, *fout;
    int n, m, i, y, nr, j, a, b;
    fin=fopen("lca.in", "r");
    fout=fopen("lca.out", "w");
    fscanf(fin, "%d%d", &n, &m);
    y=1;
    for(i=2;i<=n;i++){
        fscanf(fin, "%d", &nr);
        f[y]=i;
        urm[y]=lst[nr];
        lst[nr]=y;
        y++;
    }
    euller(1);
    n=n*2-1;
    for(i=1;i<=n;i++){
        r[i][0]=eul[i];
        for(j=1;(1<<j)<=i;j++)
            r[i][j]=minim(r[i-(1<<(j-1))][j-1], r[i][j-1]);
    }
    logg[1]=0;
    for(i=2;i<=100000;i++)
        logg[i]=1+logg[i/2];
    for(i=0;i<m;i++){
        fscanf(fin, "%d%d", &a, &b);
        fprintf(fout, "%d\n", intreb(poz[b], poz[a]));
    }
    //for(i=1;i<=n;i++)
        //printf("%d ", eul[i]);
    fclose(fin);
    fclose(fout);

    return 0;
}