#include <iostream>

using namespace std;

int main() {
	int p;
	cin >> p;
	long long n[p + 1];  // |{ x | 1<=x<=10^i, f(x)=true }|
	n[1] = 3;
	long long powered = 10;
	for (int i = 2; i <= p; ++i, powered *= 10) {
		n[i] = (n[i - 1] * 9 + 9) + (powered - 1);
	}
	cout << n[p] << endl;
	return 0;
}