func main() {
prod := bigint.BigInt{[]int{1}}
for i := 0; i < 1000; i++ {
prod.Mult(2)
}
println(prod.DigitSum())
}
func main() {
fact := bigint.BigInt{[]int{1}}
for i := 1; i <= 100; i++ {
fact.Mult(i)
}
println(fact.String())
println(fact.DigitSum())
}