#include<iostream>

using namespace std;

struct Point{double x,y;};
Point in[4];

bool solve(int num){

  int x = 0,y = 0;
  
  for(int i = 0; i < 4; i++) {
    if(in[num].x == in[i].x) x++;
    if(in[num].y == in[i].y) y++;
  }
  if(x != 2 || y != 2) return false;
  return true;
}
int main(){
  while(1){
    char c;

    for(int i = 0; i < 4; i++)
      if(i == 3) cin >> in[i].x >> c >> in[i].y;
      else if(!(cin >> in[i].x >> c >> in[i].y >> c)) return 0;


    bool ans = true;

    for(int i = 0; i < 4; i++) ans = (ans && solve(i));

    if(ans) cout << "YES" << endl;
    else cout << "NO" << endl;
  }
  return 0;
}