#include <cstdio>
#include <algorithm>
#include <cmath>

using namespace std;

int n, m, a[200000][18],c[100001],p=2,w[100001],l[100001],r,q;
bool e;

void eul(int x)
{
	e=0;
	for(int i=1;i<n;i++)
	{
		if(c[i]==x)
		{
			a[p][0]=i+1;
			w[i+1]=p;
			p++;
			eul(i+1);
			a[p][0]=x;
			p++;
		}
	}
}

int main()
{
    freopen("lca.in","r",stdin);
    freopen("lca.out","w",stdout);
    scanf("%d %d\n",&n,&m);
    l[1]=0;
    for(int i=2; i<=2*n-1; i++)
		l[i]=l[i/2]+1;
    for(int i=1; i<n; i++)
		scanf("%d",&c[i]);
	a[1][0]=1;
	eul(1);
	p=1;
	for(int i=1; i<=l[2*n-1];i++)
	{
		p*=2;
		for (int j=1; j<=2*n-p ;j++)
			a[j][i]=min(a[j][i-1],a[j+p/2][i-1]);
	}
	for (int i=1; i<=m; i++)
	{
		scanf("%d %d",&q,&r);
		r=w[r];
		q=w[q];
		if(r<q)
			swap(r,q);
		p=pow(2,l[r-q+1]);
		printf("%d\n",min(a[q][l[r-q+1]],a[r-p+1][l[r-q+1]]));
	}
    return 0;
}