import "math/big"

type MyBigInt struct {
	*big.Int
}

func Int(v *big.Int) MyBigInt {
	return MyBigInt{v}
}

func (a MyBigInt) + (b MyBigInt) MyBigInt {
	return MyBigInt{new(big.Int).Add(a.Int, b.Int)}
}

func (a MyBigInt) += (b MyBigInt) {
	a.Int.Add(a.Int, b.Int)
}

func -(a MyBigInt) MyBigInt {
	return MyBigInt{new(big.Int).Neg(a.Int)}
}

a := Int(1r)
a += Int(2r)
println(a + Int(3r))
println(-a)