#include <fstream>
#include <vector>
#include <cmath>

using namespace std;

const int maxn = 100010;
int t[maxn], p[maxn], level[maxn];
vector <int> sons[maxn];	

int findLevel(int nod) {
	int max = 1;
	for (int i = 0; i < sons[nod].size(); i++) {
		level[sons[nod][i]] = level[nod] + 1;
		int x = findLevel(sons[nod][i]);
		if (x > max) 
			max = x;	
	}	
	if (sons[nod].size() == 0)
		return level[nod];
	return max;
}

void findSegment(int nod, int r) {
	if (level[nod] <= r)
		p[nod] = 1;
	else 
		if (level[nod] % r == 1)
			p[nod] = t[nod];
		else 
			p[nod] = p[t[nod]];
			
	for (int i = 0; i < sons[nod].size(); i++)
		findSegment(sons[nod][i], r);
}

int findAncestor(int a, int b) {
	while (p[a] != p[b]) {
		if (level[p[a]] > level[p[b]])
			a = p[a];
		else 
			b = p[b];
	}
	
	while (a != b) {
		a = t[a];
		b = t[b];	
	}
	
	return a;
}

int main() {
	ifstream f("lca.in");
	ofstream g("lca.out");
	
	int n, m;
	f >> n >> m;
	
	int x;
	t[1] = 0;
	level[1] = 1;
	for (int i = 2; i <= n; i++) {
		f >> x;
		t[i] = x;
		sons[x].push_back(i);	
	}
	
	int max_level = findLevel(1);
	int r = sqrt(max_level);
	
	findSegment(1, r);
	
	int a, b;
	for (int li = 1; li <= m; li++) {
		f >> a >> b;	
		int x = findAncestor(a, b);
		g << x << '\n';
	}
	
	return 0;
}