import java.io.*;
public class Jrk{
  public static void main(String argumendid[]) throws IOException{
    BufferedReader sisse=new BufferedReader(
      new FileReader("Th.txt")
 );
String rida=sisse.readLine();
int korda=0;
  while(rida!=null){
      if(rida.equals("re"))korda=korda+1;
 rida=sisse.readLine();
      }   
System.out.println(korda);
sisse.close();   
}
}