// verifast_options{disable_overflow_check target:ILP32}
extern void abort(void);
//@ requires true;
//@ ensures true;


void reach_error()
//@ requires false;
//@ ensures true;
{}void assume_abort_if_not(int cond) 
//@ requires true;
//@ ensures true;
{  if(!cond) {abort();}
}
void __VERIFIER_assert(int cond) 
//@ requires (cond != 0);
//@ ensures (cond != 0);
{  if (!(cond)) {
      ERROR: {reach_error();abort();}
  }
  return;
}
int __VERIFIER_nondet_int();
//@ requires true;
//@ ensures true;
int main() 
//@ requires module(ddlm2013__verifast_instrumented, true);
//@ ensures junk();
{
    //@ open_module(); 
    unsigned int i,j,a,b;
    int flag = __VERIFIER_nondet_int();
    a = 0;
    b = 0;
    j = 1;
    if (flag) {
        i = 0;
    } else {
        i = 1;
    }
while (__VERIFIER_nondet_int())
//@ invariant ((flag == 0) || (((0 == (i % 2)) && (a == b)) && ((( a + 1) % 4294967296) == ((( b + j) + ( i * 4294967295)) % 4294967296))));
    {
        a++;
        b += (j - i);
        i += 2;
        if (i%2 == 0) {
            j += 2;
        } else {
            j++;
        }
    }
    if (flag) {
        __VERIFIER_assert(a == b);
    }
    return 0;
}