// verifast_options{disable_overflow_check target:ILP32}

/* extended Euclid's algorithm */
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", "egcd3-ll.c", 4, "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(egcd3_ll_valuebound2__verifast_instrumented_modified, true); 
//@ ensures junk();
{
    int x, y;
    long long a, b, p, q, r, s;
    x = __VERIFIER_nondet_int();
    assume_abort_if_not(x>=0 && x<=2);
    y = __VERIFIER_nondet_int();
    assume_abort_if_not(y>=0 && y<=2);
    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 ((((((((((b == 1) && (s == 0)) && (p == 0)) && (r == 1)) && (a == y)) && (x == 1)) && (a == 2)) && (q == 1)) || ((((((((1 <= x) && (y <= 2)) && (b == 0)) && ((((q * x) + a) + (y * s)) == ((y * r) + (p * x)))) && (a == ((y * r) + (p * x)))) && (1 <= a)) && (1 <= y)) && (x <= 2))) || ((((((((((r == 0) && (y <= 2)) && (s == 1)) && (1 <= a)) && (b == y)) && (q == 0)) && (1 <= y)) && (a == x)) && (x <= 2)) && (p == 1)));
 {
        if (!(b != 0))
            break;
        long long c, k;
        c = a;
        k = 0;

        while (1)//@ invariant ((((((((((((((r == 0) && (s == 1)) && ((c + 1) <= (b * 2))) && (1 <= a)) && (b == y)) && (q == 0)) && (c == 0)) && (a == x)) && ((y + (k * y)) == (b + x))) && (x <= 2)) && (p == 1)) || ((((((((((b == 1) && (s == 0)) && (p == 0)) && (k == 0)) && (r == 1)) && (a == y)) && (c == 2)) && (x == 1)) && (a == 2)) && (q == 1))) || ((((((((((((r == 0) && (y <= 2)) && (k == 0)) && (s == 1)) && (1 <= a)) && (b == y)) && (q == 0)) && (1 <= y)) && (a == x)) && (c == x)) && (x <= 2)) && (p == 1))) || ((((((((((y == 2) && (b == 1)) && (s == 0)) && (p == 0)) && (r == 1)) && (x == 1)) && (k == 2)) && (a == 2)) && (c == 0)) && (q == 1)));
 {
            if (!(c >= b))
                break;
            long long d, v;
            d = 1;
            v = b;

            while (1)//@ invariant (((((((((((((((y == 2) && (b == 1)) && (s == 0)) && (p == 0)) && (k == 0)) && (r == 1)) && (c == 2)) && (v == 1)) && (x == 1)) && (d == 1)) && (a == 2)) && (q == 1)) || (((((((((((((v == (d * b)) && (r == 0)) && (k == 0)) && (v <= c)) && (s == 1)) && (b == y)) && (b <= c)) && (q == 0)) && (1 <= y)) && (a == x)) && (c == x)) && (x <= 2)) && (p == 1))) || (((((((((((((y == 2) && (b == 1)) && (v <= 1)) && (s == 0)) && (p == 0)) && (k == 0)) && (r == 1)) && (c == 2)) && (x == 1)) && ((d % 2) == 0)) && (a == 2)) && (q == 1)) && (d == v))) || ((((((((((((y == 2) && (b == 1)) && (s == 0)) && (p == 0)) && (k == 0)) && (r == 1)) && (c == 2)) && (x == 1)) && (v == 2)) && (d == 2)) && (a == 2)) && (q == 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;
}