#include<iostream>
#include<vector>
using namespace std;
int main()
{
	int N;
	cin>>N;
	N--;
	vector<pair<int,int> >T;
	for(int a=1;a<=9;a++)for(int b=a+1;b<=9;b++)T.push_back(make_pair(a,b));
	int c=N/T.size();
	pair<int,int>p=T[N%T.size()];
	cout<<p.first;
	for(int i=0;i<=c;i++)cout<<p.second;
	cout<<endl;
}