#include <iostream> using namespace std; int fum( int n) { int t,sum,a;sum=t=0;a=2; while (n>0) { t=t+a; a=a*10; sum=sum+t; n--; } return sum; } int main() { int n,sn; cin>>n; sn=fum(n); cout<<sn<<endl; return 0; }