factorial n = factorial_helper 1 n
factorial_helper prod n =
if n> 0 then
factorial_helper (prod*n) (n-1)
else
prod
main
= print (factorial
5)
ZmFjdG9yaWFsIG4gPSBmYWN0b3JpYWxfaGVscGVyIDEgbgoKZmFjdG9yaWFsX2hlbHBlciBwcm9kIG4gPSAKICAgaWYgbj4gMCB0aGVuCiAgICAgIGZhY3RvcmlhbF9oZWxwZXIgKHByb2QqbikgKG4tMSkKICAgZWxzZQogICAgICBwcm9kIAoKCgptYWluID0gcHJpbnQgKGZhY3RvcmlhbCA1KQ==