#include <stdio.h>

int main(void) {

  int a = 3, b = 4;

  if (a == 1)
    if (b == 2)
      printf("A\n");
    else 
      printf("B\n"); 

  if (a == 1) 
    if (b == 2)
      printf("C\n");
  else 
    printf("D\n"); 

  if (a == 1){ 
    if (b == 2)
      printf("E\n");} 
  else 
    printf("F\n"); 
  
  return 0;
}