return -1
	}
	return tmp1.Int64()
}

func nextTerm(k int64) {
	y2 := k*2 + 1
	accum.Add(accum, tmp1.Lsh(numer, 1))
	accum.Mul(accum, tmp1.SetInt64(y2))
	numer.Mul(numer, tmp1.SetInt64(k))
	denom.Mul(denom, tmp1.SetInt64(y2))
}

func eliminateDigit(d int64) {
	accum.Sub(accum, tmp1.Mul(denom, tmp1.SetInt64(d)))
	accum.Mul(accum, ten)
	numer.Mul(numer, ten)
}

func main() {
	i := 0
	k := int64(0)