// verifast_options{disable_overflow_check target:ILP32}

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

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", "geo2-ll.c", 8, "reach_error"); }
extern int __VERIFIER_nondet_int(void);//@ requires true; 
//@ ensures true;

extern void abort(void);
void assume_abort_if_not(int cond) //@ requires true; 
//@ ensures (cond != 0);
{
  if(!cond) {abort();}
}
void __VERIFIER_assert(int cond) //@ requires (1 <= cond); 
//@ ensures (1 <= cond);
{
    if (!(cond)) {
    ERROR:
        {reach_error();}
    }
    return;
}


int main() //@ requires module(geo2_ll_valuebound20__verifast_instrumented_modified, true); 
//@ ensures junk();
{
    int z, k;
    unsigned long long x, y, c;
    z = __VERIFIER_nondet_int();
    assume_abort_if_not(z>=0 && z<=20);
    k = __VERIFIER_nondet_int();
    assume_abort_if_not(k>=0 && k<=20);

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

    while (1)//@ invariant (((z <= 20) && ((((((z * x) + ((18446744073709551615U * z) * y)) + (18446744073709551615U * x)) + 1) % (1 <  < 64)) == 0)) && (0 <= z));
 {
        __VERIFIER_assert(1 + x*z - x - z*y == 0);

        if (!(c < k))
            break;

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