// verifast_options{disable_overflow_check target:ILP32}
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 SIZE = 20000001;
unsigned int __VERIFIER_nondet_uint();
//@ requires integer(&SIZE, ?veri_req_SIZE) &*& true;
//@ ensures integer(&SIZE, ?veri_ens_SIZE) &*& true;
int main() 
//@ requires module(sumt2__verifast_instrumented, true);
//@ ensures junk();
{
    //@ open_module(); 
  unsigned int n,i,j,l=0;
  n = __VERIFIER_nondet_uint();
  if (!(n <= SIZE)) return 0;
  i = 0;
  j = 0;
  l=0;
while( l < n )
//@ invariant integer(&SIZE, ?veri_inv_SIZE) &*& ((( i + j) % 4294967296) == l);
    {
	
	  if(!(l%2))
	    i = i + 1;
	  else 
		  j = j+1;
    l = l+1;
  }
  __VERIFIER_assert((i+j) == l);
  return 0;
}