inport java.util.Scanner;

public class main{
public static void main(String[] args) {
  System.err.print("N");
  int N = scanner.NextInt();

  
  if(o<=N<=100, N/2 == 0){
  System.out.println(N/2);
  }
  else(o<=N<-100, N/2 == 1){
  System.out.println(N/2 + 1);  
  }
  else(
  System.out.println("error");
  )
}
}