void abort() { };
                                            
  
                                                             
  
                                      

                        
                                                                                                                                                          
                                                                      
extern int __VERIFIER_nondet_int();
/*@ 
    requires ((\old(cond) != 0)) && (cond != 0);
    ensures ((\old(cond) != 0)) && (1);
@*/
void __VERIFIER_assert(int cond) {
  if (!(cond)) {
    ERROR: {/*@ assert(0); */;abort();}
  }
  return;
}
int main() {
  unsigned int x = 0;
/*@
loop invariant (((x % 4) == 0));
@*/
  while (__VERIFIER_nondet_int()) {
    x += 4;
  }
  __VERIFIER_assert(!(x % 4));
  return 0;
}