I have been trying to solve this Problem F. Here i am using set of custom data as below

```
struct data{
ll x,y;
int n;
bool operator()(const data& a, const data& b){
return (a.x==b.x)?(a.y<b.y):(a.x<b.x);
}
friend bool operator < (const data& a, const data& b){
return (a.x==b.x)?(a.y<b.y):(a.x<b.x);
}
friend bool operator > (const data& a, const data& b){
return (a.x==b.x)?(a.y>b.y):(a.x>b.x);
}
};
set<data> st;
```

I am doing Insert, erase, lower_bound operation on this set. which is working fine on my Ubantu, but giving compilation error as "template argument 1 is invalid". The problem is in the set data structure so tried to debug it from this stackoverflow thread,tried to subit it in different c++ virsions too,but none of them is working,(some of it are working fine on my machine, but not on atcoder judge.

My submissions one. and another implementation of set::comp()

HELP Thanks in Advance;