//#include "pch.h"
#include <algorithm>
#include <iostream>
#include <vector>
#include <iomanip>
#include <random>
#include <queue>
#include <string>
#include <map>
#include <unordered_set>
using namespace std;

int main() {
	double p = 0;
	unsigned long long int n, k, a = 0 , b;
	cin >> n >> k;
	string s = to_string(n);
	int sum = 0;
	for (int i = 0; i < s.size(); ++i) {
		sum += s[i] - '0';
	}
	if (n % 5 == 0 || n % 6 == 0) {
		p = 1;
	}
	if (sum % 3 == 0) {
		for (int i = 0; i < s.size(); ++i) {
			if (((s[i] - '0') % 2) == 0 || (s[i] - '0') % 5 == 0) {
				++a;
			}
		}
	}
	else {
		for (int i = 0; i < s.size(); ++i) {
			if (((s[i] - '0') % 5) == 0) {
				++a;
			}
		}
	}
	if (a == 0) {
		cout << 0;
		return 0;
	}
	b = s.size() - a;
	//cout << a << ' ' << b << endl;
	double t = double((s.size() - 1)*(s.size() - 2)) / 2;
	double q = double(s.size() * (s.size() - 1) )/ 2;
	//cout << p << ' ' << q << endl;
	for (int i = 0; i < k; ++i) {
		//p = (t + (a - 1) * p + (t + a) * (1 - p)) / q;
		//p = (t + (a - 1) * p + (t + a) * (1 - p)) / q;
		//p = ((t + (a - 1)) * p + (t + a) * (1 - p)) / q;
		p = ((t + a - 1) * p + a * (1 - p)) / q;
		//cout << p << endl;
	}
	std::cout << std::fixed << std::setprecision(9) << p;
	return 0;
}