#include <bits/stdc++.h>
#define ull unsigned long long
#define FILES freopen("lca.in","r",stdin);\
              freopen("lca.out","w",stdout);
#define CMAX 15485863
#define fastio std::ios_base::sync_with_stdio(NULL),cin.tie(NULL),cout.tie(NULL);
#define mp make_pair
#define INF 1e18
#define mod 666013
#define ll long long
#define SMAX 300
#define MAX 100000
#define pb push_back
#define add emplace_back
#define void inline void
#define int ll
using namespace std;
bool check[MAX+5];
int n,m,f[MAX+5], cost[MAX+5], a, b, best = -1;
pair<int,int> ans;
vector<int>v[MAX+5];
vector<pair<int,int>> rmq[MAX+5];
vector<pair<int,int>> euler;
void dfs(int x, int h)
{
    check[x] = 1;
    euler.add(mp(x,h));
    f[x] = euler.size();
    for(auto i : v[x])
    {
        if(!check[i])
        {
            dfs(i,h+1);
            euler.add(mp(x,h));
        }
    }
}
pair<int,int> Min(pair<int,int> a,pair<int,int> b)
{
    return (a.second > b.second ? b : a);
}
pair<int,int> Lca(int a,int b)
{
    int d = max(f[a],f[b]) - min(f[a],f[b]) + 1, p = 1, e = 0;
    while(p <= d) p *= 2, e++;
    p >>= 1, e--;
    return Min(rmq[e][min(f[a],f[b])-1],rmq[e][max(f[a],f[b]) - p]);
}
signed main()
{
    fastio
    FILES
    cin >> n >> m;
    for(int i = 1;i < n; ++i)
    {
        cin >> a;
        v[i+1].add(a), v[a].add(i+1);
    }
    dfs(1,1);
    for(int i = 0;i < euler.size(); ++i)
        rmq[0].add(euler[i]);
    int cnt = euler.size(), tot = euler.size();
    for(int i = 1;i <= log2(cnt); ++i)
    {
        tot -= (1 << (i - 1));
        for(int j = 1;j <= tot; ++j)
            rmq[i].add(Min(rmq[i-1][j-1],rmq[i-1][j+(1<<(i-1))-1]));
    }
    for(int i = 1;i <= m; ++i)
    {
        int a,b;
        cin >> a >> b;
        pair<int,int> lca = Lca(a,b);
        cout << lca.first << '\n';
    }
}