use proconio::input;

fn main(){
  input!{
    A: i64,
    B: i64,
    N: i64,
    M: i64,
  }
  if A>B{
    println!("{}",B+(A-B)/(N+1));
  }
  else{
    println!("{}",A+(B-A)/(M+1));
  }
}