題意：給出一顆樹，每次詢問樹上兩個節點到根的距離誰更近。。

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <string>
#include <vector>
#include <queue>
using namespace std;

#define REP(i,s,t) for(int (i)=(s);(i)<=(t);++(i))
#define UREP(i,s,t) for(int (i)=(s);(i)>=(t);--(i))
#define INF 0x7FFFFFFF

const int maxn = 100000+5;
int d[maxn], pa[maxn];
int n, m;

int Find(int x) {
    if (x == pa[x]) return x;
    int t = pa[x];
    pa[x] = Find(pa[x]);
    d[x] += d[t];
    return pa[x];
}

int main() {
    //freopen("input.in", "r", stdin);
    while (scanf("%d%d",&n, &m) && (n|m)) {
        int a, b;
        memset(d, 0, sizeof(d));
        for (int i=1;i<=n;++i) pa[i] = i;
        for (int i=0;i<n-1;++i) {
            scanf("%d%d",&a, &b);
            pa[b] = a;
            d[b] = 1;
        }
        for (int i=1;i<=n;++i) Find(i);
        //for (int i=1;i<=n;++i) printf("%d ", d[i]);putchar('\n');
        for (int i=0;i<m;++i) {
            scanf("%d%d",&a, &b);
            if (d[a]-1 < d[b])
                printf("lxh\n");
            else
                printf("pfz\n");
        }
    }
    return 0;
}