#include<fstream>
#include<vector>
using namespace std;
vector<int> L[200005];
bool u[200005];
int n, m, i, j, x, y, v[200005], q[18][200005], prim[200005], nq, p;
void dfs_euler(int nod)
{
    q[0][++nq]=nod;
    prim[nod]=nq;
    for(int i=0; i<L[nod].size(); i++)
    {
        int fiu=L[nod][i];
        dfs_euler(fiu);
        q[0][++nq]=nod;
    }
}
ifstream in("lca.in");
ofstream out("lca.out");
int main()
{
    in>>n>>m;
    for(i=2; i<=n; i++)
    {
        in>>x;
        L[x].push_back(i);
    }
    dfs_euler(1);
    for(i=1; (1<<i)<=nq; i++)
    {
        for(j=1; j<=nq; j++)
        {
            q[i][j]=q[i-1][j];
            if(j+(1<<(i-1))<=nq)
                q[i][j]=min(q[i-1][j], q[i-1][j+(1<<(i-1))]);
        }
    }
    for(i=2; i<=nq; i++)
        v[i]=v[i/2]+1;
    for(;m--;)
    {
        in>>x>>y;
        x=prim[x];
        y=prim[y];
        if(y<x)
            swap(x, y);
        p=v[y-x+1];
        out<<min(q[p][x], q[p][y-(1<<p)+1])<<"\n";
    }
    return 0;
}