#include <iostream>
#include <fstream>
#include <vector>
#include <cmath>
#include <algorithm>
using namespace std;
ifstream f("lca.in");
ofstream g("lca.out");
vector <int> v[1000005];
int viz[100005],d[100005][35],i,x,y,j,lvl,p,m,n,k,niv[100005],nod[100005],poz[100005],a;
void dfs(int s)
{viz[s]=1;
for(int i:v[s])
    if(!viz[i])
        {nod[++k]=s;
        poz[s]=k;
        dfs(i);
        }
nod[++k]=s; 
poz[s]=k;      
}
int main()
{f>>n>>m;
for(i=2;i<=n;i++)
    {f>>x;
    v[i].push_back(x);
    v[x].push_back(i);
    niv[i]=niv[x]+1;
    }
for(i=1;i<=n;i++)
sort(v[i].begin(),v[i].end());
dfs(1);
for(i=1;i<=k;i++)
    d[i][0]=nod[i];
//for(i=1;i<=k;i++)cout<<d[i][0]<<" ";
for(j=1;(1<<j)<=k;j++)
    for(i=1;i+(1<<j)-1<=k;i++)
        {if(niv[d[i][j-1]]<niv[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(niv[d[x][p]]<niv[d[y-(1<<p)+1][p]])a=d[x][p];
        else a=d[y-(1<<p)+1][p];
    g<<a<<'\n';
    }
}