// verifast_options{disable_overflow_check target:ILP32}
/* extended Euclid's algorithm */
extern void abort(void);
//@ requires true;
//@ ensures true;
void reach_error()
//@ requires false;
//@ ensures true;
{}extern int __VERIFIER_nondet_int(void);
//@ requires true;
//@ ensures true;
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(egcd3_ll_valuebound1__verifast_instrumented, true);
//@ ensures junk();
{
    //@ open_module(); 
    int x, y;
    long long a, b, p, q, r, s;
    x = __VERIFIER_nondet_int();
    assume_abort_if_not(x>=0 && x<=1);
    y = __VERIFIER_nondet_int();
    assume_abort_if_not(y>=0 && y<=1);
    assume_abort_if_not(x >= 1);
    assume_abort_if_not(y >= 1);

    a = x;
    b = y;
    p = 1;
    q = 0;
    r = 0;
    s = 1;

while (1)
//@ invariant (((((((((a == 1) && (b == 0)) && (p == 0)) && (y == 1)) && (r == 1)) && (x == 1)) && (q == 1)) && ((s + 1) == 0)) || ((((((((a == 1) && (r == 0)) && (b == 1)) && (y == 1)) && (s == 1)) && (x == 1)) && (q == 0)) && (p == 1)));
    {
        if (!(b != 0))
            break;
        long long c, k;
        c = a;
        k = 0;

while (1)
//@ invariant (((((((((((a == 1) && (r == 0)) && (b == 1)) && (y == 1)) && (s == 1)) && (x == 1)) && (k == 1)) && (q == 0)) && (c == 0)) && (p == 1)) || ((((((((((a == 1) && (r == 0)) && (b == 1)) && (y == 1)) && (k == 0)) && (s == 1)) && (x == 1)) && (q == 0)) && (c == 1)) && (p == 1)));
    {
            if (!(c >= b))
                break;
            long long d, v;
            d = 1;
            v = b;

while (1)
//@ invariant ((((((((((((a == 1) && (r == 0)) && (y == 1)) && (k == 0)) && (s == 1)) && (v == 1)) && (b == y)) && (d == 1)) && (q == 0)) && (a == x)) && (c == x)) && (p == 1));
    {
                __VERIFIER_assert(a == y * r + x * p);
                __VERIFIER_assert(b == x * q + y * s);
                __VERIFIER_assert(a == k * b + c);
                __VERIFIER_assert(v == b * d);

                if (!(c >= 2 * v))
                    break;
                d = 2 * d;
                v = 2 * v;
            }
            c = c - v;
            k = k + d;
        }

        a = b;
        b = c;
        long long temp;
        temp = p;
        p = q;
        q = temp - q * k;
        temp = r;
        r = s;
        s = temp - s * k;
    }
    __VERIFIER_assert(p*x - q*x + r*y - s*y  == a);
    return 0;
}