# Problem 160: Factorial trailing digits
For any N, let f(N) be the last five digits before the trailing zeroes
in N!. For example, 9! = 362880 so f(9)=36288 10! = 3628800 so
f(10)=36288 20! = 2432902008176640000 so f(20)=17664 Find
f(1,000,000,000,000)