// verifast_options{disable_overflow_check target:ILP32}

/* 
Geometric Series
computes x=(z-1)* sum(z^k)[k=0..k-1] , y = z^k
returns 1+x-y == 0
*/

extern void abort(void);//@ requires true; 
//@ ensures true;

extern void __assert_fail(const char *, const char *, unsigned int, const char *) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__noreturn__));
void reach_error() //@ requires false; 
//@ ensures true;
{ __assert_fail("0", "geo1-ll.c", 9, "reach_error"); }
extern int __VERIFIER_nondet_int(void);//@ requires true; 
//@ ensures true;

extern void abort(void);
void assume_abort_if_not(int cond) //@ requires integer(&counter, ?veri_req_counter) &*& (veri_req_counter == 0); 
//@ ensures integer(&counter, ?veri_ens_counter) &*& (((cond != 0) && (veri_ens_counter == veri_req_counter)) && (veri_ens_counter == 0));
{
  if(!cond) {abort();}
}
void __VERIFIER_assert(int cond) //@ requires integer(&counter, ?veri_req_counter) &*& (cond == 1); 
//@ ensures integer(&counter, ?veri_ens_counter) &*& ((veri_ens_counter == veri_req_counter) && (cond == 1));
{
    if (!(cond)) {
    ERROR:
        {reach_error();}
    }
    return;
}
int counter = 0;
int main() //@ requires module(geo1_ll_unwindbound2__verifast_instrumented_modified, true); 
//@ ensures junk();
{
    int z, k;
//@ invariant integer(&counter, ?veri_req_counter) &*& (veri_req_counter == 0);
    unsigned long long x, y, c;
    z = __VERIFIER_nondet_int();
    k = __VERIFIER_nondet_int();
    assume_abort_if_not(z >= 1);
    assume_abort_if_not(k >= 1);

    x = 1;
    y = z;
    c = 1;

    while (counter++<2)//@ invariant integer(&counter, ?veri_inv_counter) &*& (((((((1 <= veri_inv_counter) && (1 <= z)) && ((z * z) == y)) && (x == (z + 1))) || ((((2 <= veri_inv_counter) && (y == ((z * z) * z))) && (1 <= z)) && (x == (((z * z) + z) + 1)))) || ((((z == y) && (x == 1)) && (veri_inv_counter == 0)) && (1 <= z))) && (veri_req_counter == 0));
 {
        __VERIFIER_assert(x*z - x - y + 1 == 0);

        if (!(c < k)) 
            break;

        c = c + 1;
        x = x * z + 1;
        y = y * z;

    }  //geo1

    x = x * (z - 1);

    __VERIFIER_assert(1 + x - y == 0);
    return 0;
}