// luogu-judger-enable-o2
include <cstdio>
//include <iostream>
include <cstring>
include <algorithm>
include <cmath>
define R(a,b,c) for(regist ......
Freddy Frog is sitting on a stone in the middle of a lake. Suddenly he notices Fiona Frog who is sitting on another stone. He plans to visit her, but ......