#include<stdio.h>
#include<vector>
using namespace std;

#define NMAX 100002

int n,m;
int nr;
int ord[NMAX],rmq[17][NMAX*2],first[NMAX];

vector<int>v[NMAX];

void dfs(int nod)
{
    int i;
    rmq[0][++nr]=ord[nod];

    for(i=0;i<v[nod].size();++i)
    {
        dfs(v[nod][i]);
        rmq[0][++nr]=ord[nod];
    }
}

void RMQ()
{
    int i,j,maxi,maxj,l=1;

    maxi=1;
    while((1<<maxi)<=nr)maxi<<=1;
    maxi>>=1;

    for(i=1;i<=maxi;++i)
    {
        l=(1<<(i-1));

        maxj=nr-(1<<i)+1;
        for(j=1;j<=maxj;++j)
            rmq[i][j]=min(rmq[i-1][j], rmq[i-1][j+l]);
    }
}

int main()
{
    freopen("lca.in","r",stdin);
    freopen("lca.out","w",stdout);
    int i,j,x,y,d;
    scanf("%d%d",&n,&m);

    for(i=2;i<=n;++i)
    {
        scanf("%d",&x);
        v[x].push_back(i);
    }

    for(i=1;i<=n;++i)
        ord[i]=i;


    nr=0;
    dfs(1);

    RMQ();

    for(i=1;i<=nr;++i)
        if(!first[ord[rmq[0][i]]])
            first[ord[rmq[0][i]]]=i;



    for(i=1;i<=m;++i)
    {
        scanf("%d%d",&x,&y);

        x=first[x];
        y=first[y];

        if(x>y)
        {
            d=x;
            x=y;
            y=d;
        }

        d=y-x+1;

        j=1;
        while((1<<j)<=d)++j;
        --j;

         printf("%d\n",min(rmq[j][x] , rmq[j][y-(1<<j)+1]));
    }

    return 0;
}