#include <iostream>
using namespace std;
typedef long long int		s64;
s64 N = 100000000000000LL;
s64 M = 10000000LL;
s64 D = 12;

s64 Pow(s64 base, s64 exp)
{
	s64 ret = 1;
	for (s64 i = 0; i < exp; i ++) ret *= base;
	return ret;
}

s64 GCD(s64 x, s64 y){
	return x ? GCD(y % x, x) : y;
}

s64 Naive()
{
	s64 r = 0;
	for (s64 n=1; n<=N; n++) {
		for (s64 d=1; d<=N; d++) {
			s64 g = GCD(n, d);
			s64 m = d / g;
			s64 a2 = 0, a5 = 0;
			while (m%2 == 0) { m /= 2;	a2 ++; }
			while (m%5 == 0) { m /= 5;	a5 ++; }
			if (m != 1) continue;
			if (max(a2,a5) != D) continue;
			r ++;
		}
	}
	return r;
}

s64 Func1(s64 d)
{
	s64 r = 0, k;
	r += (N/d) * (d - d/5);
	for (s64 m=d+1; ; m+=1) {
		if (m%5==0) continue;
		k = N / m;
		if (k <= M) break;
		r += k;
	}
	for (; k>0; k--) {
		s64 n1 = N/k - max(N/(k+1), d);
		s64 n2 = N/k/5 - max(N/(k+1)/5, d/5);
		r += k * (n1 - n2);
	}
	return r;
}

s64 Func2(s64 d)
{
	s64 r = 0, k;
	r += (N/d) * (d/2);
	for (s64 m=d+1; ; m+=2) {
		k = N / m;
		if (k <= M) break;
		r += k;
	}
	for (; k>0; k--) {
		s64 n = (N/k-1)/2 - max((N/(k+1)-1)/2, (d-1)/2);
		r += k * n;
	}
	return r;
}


s64 Func3(s64 d)
{
	s64 k;
	s64 r = (N/d) * ((d-1)/2 - (d-5)/10);
	for (s64 m=(d%2==0)?d+1:d+2; ; m+=2) {
		if (m%5==0) continue;
		k = N / m;
		if (k <= M) break;
		r += k;
	}
	for (; k>0; k--) {
		s64 n1 = (N/k-1)/2 - max((N/(k+1)-1)/2, (d-1)/2);
		s64 n2 = (N/k-5)/10 - max((N/(k+1)-5)/10, (d-5)/10);
		r += k * (n1 - n2);
	}
	return r;
}

s64 Smart()
{
	s64 r = Func1(Pow(5, D)) + Func2(Pow(2, D));
	for (s64 q=1; q<=D-1; q++) {
		s64 r0 = Func3(Pow(2, D) * Pow(5, q));
		if (r0 == 0) break;
		r += r0;
	}
	for (s64 p=1; p<=D; p++) {
		s64 r0 = Func3(Pow(2, p) * Pow(5, D));
		if (r0 == 0) break;
		r += r0;
	}
	return r;
}

int main()
{
	s64 r = Smart();
	cout << "C(" << N << "," << D << ") = " << r << endl;
}