#include <iostream>
#include <algorithm>
#include <functional>
#include <string>
#include <climits>
#include <vector>
#include <numeric>
#include <complex>
#include <iomanip>
using namespace std;

//#define __int64 long long
//#define long __int64
#define REP(i,a,b) for(int i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)
const int Vecy[4] = {0,-1,0,1};
const int Vecx[4] = {1,0,-1,0};

long long func(int n){
	if(n == 1){
		return 3;
	}else{
		return (func(n - 1) + 1) * 9 + (long long)(pow(10, n - 1) + 0.2) - 1;
	}
}

int main(){
	int n;
	cin >> n;
	
	cout << func(n) << endl;
    
    return 0;
}