#include <fstream>
#include <iostream>
#include <vector>
#include <cmath>
using namespace std;
ifstream f("lca.in");
ofstream g("lca.out");
int d[200005][20],euler[400005],poz[200005],h[200005],nr;
vector<int> v[200005];
void dfs(int nod)
{int i;
euler[++nr]=nod;
poz[nod]=nr;
for(i=0;i<v[nod].size();i++)
    if(h[v[nod][i]]==0)
        {h[v[nod][i]]=h[nod]+1;
        dfs(v[nod][i]);
        euler[++nr]=nod;

        }

}
int main()
{int n,m,t,i,j,aux,x,y,p,a;
f>>n>>m;
for(i=2;i<=n;i++)
    {f>>t;
    v[t].push_back(i);

    }
dfs(1);
for(i=1;i<=nr;i++)d[i][0]=euler[i];
for(j=1;(1<<j)<=nr;j++)
    for(i=1;i+(1<<j)-1<=nr;i++)
    if(h[d[i][j-1]]<h[d[i+(1<<(j-1))][j-1]])d[i][j]=d[i][j-1];
    else d[i][j]=d[i+(1<<(j-1))][j-1];
for(i=1;i<=m;i++)
    {f>>x>>y;
    x=poz[x];y=poz[y];
    if(x>y)swap(x,y);
    p=log2(y-x+1);
    if(h[d[x][p]]<h[d[y-(1<<p)+1][p]])a=d[x][p];
    else a=d[y-(1<<p)+1][p];
    g<<a<<'\n';

    }
    return 0;
}