package problems;

public class PE160 {

    public static long solve(long N, int k) {
        int mod = 1; for (int i=0; i<k; i++) mod*=10;

        // factorials excluding multiples of 5 and dividing by 2 for each such multiple
        long[] prods = new long[mod+1];
        prods[0] = 1;
        long prod = 1;
        for (int i=1; i<=mod; i++) {
            if (i%5==0) prod/=2;
            else prod = (prod*i) % (10*mod);
            prods[i] = prod%mod;
        }

        long res = 1;

        while (N > 0) {
            // we have N/mod of these
            long count = N/mod;
            for (int i=0; i<count; i++)
                res = (res * prods[mod]) % mod;
            // and what remains
            res = (res * prods[(int)(N%mod)]) % mod;

            // we excluded N/5 numbers
            N /= 5;
        }

        return res;
    }

    public static void solve(){
        System.out.println(solve(1000000000000L, 5));
    }

    public static void main(String[] args) {
        solve();
    }
}