extern unsigned int __VERIFIER_nondet_uint();
void abort() { };
                                                                                                                                                          
                                                                           

unsigned int id(unsigned int x);
unsigned int id2(unsigned int x);

/*@ 
    requires (1);
    ensures ((\result < 3));
@*/
unsigned int id(unsigned int x) {
  if (x==0) return 0;
  unsigned int ret = id2(x-1) + 1;
  if (ret > 2) return 2;
  return ret;
}

unsigned int id2(unsigned int x) {
  if (x==0) return 0;
  unsigned int ret = id(x-1) + 1;
  if (ret > 2) return 2;
  return ret;
}

int main() {
  unsigned int input = __VERIFIER_nondet_uint();
  unsigned int result = id(input);
  if (result == 3) {
    ERROR: {/*@ assert(0); */;abort();}
  }
}