// verifast_options{disable_overflow_check target:ILP32}
int SIZE = 50000001;


int __VERIFIER_nondet_int();
//@ requires integer(&SIZE, ?veri_req_SIZE) &*& true;
//@ ensures integer(&SIZE, ?veri_ens_SIZE) &*& true;
extern void abort(void);
//@ requires integer(&SIZE, ?veri_req_SIZE) &*& true;
//@ ensures integer(&SIZE, ?veri_ens_SIZE) &*& true;
void reach_error()
//@ requires false;
//@ ensures true;
{}void assume_abort_if_not(int cond) 
//@ requires integer(&SIZE, ?veri_req_SIZE) &*& true;
//@ ensures integer(&SIZE, ?veri_ens_SIZE) &*& true;
{  if(!cond) {abort();}
}
void __VERIFIER_assert(int cond) 
//@ requires integer(&SIZE, ?veri_req_SIZE) &*& (cond != 0);
//@ ensures integer(&SIZE, ?veri_ens_SIZE) &*& (cond != 0);
{  if (!(cond)) {
    ERROR: {reach_error();abort();}
  }
  return;
}


int main() 
//@ requires module(loopv1__verifast_instrumented, true);
//@ ensures junk();
{
    //@ open_module(); 
  int n,i,j;
  n = __VERIFIER_nondet_int();
  if (!(n <= SIZE)) return 0;
  i = 0; j=0;
while(i<n)
//@ invariant integer(&SIZE, ?veri_inv_SIZE) &*& ((i % 3) == 0);
    {
 
    if(__VERIFIER_nondet_int())	  
      i = i + 6; 
    else
     i = i + 3;    
  }
  __VERIFIER_assert( (i%3) == 0 );
  return 0;
}