#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
//using mint = static_modint<998244353>;
//using mint = modint;
using mint = static_modint<1000000007>;
using vm = vector<mint>;
using vvm = vector<vm>;
ostream &operator<<(ostream &o,const mint &m){cout<<m.val();return o;}
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using pl = pair<ll,ll>;
#define rep(i,n) for(ll i=0;i<(ll)(n);++i)
#define reps(i,s,n) for(ll i=(s);i<(ll)(n);++i)
#define rep1(i,n) for(ll i=1;i<=(ll)(n);++i)
#define ts(i) to_string(i)
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
const long long INF = 1e18;

#ifdef DEBUG
#include <debug.hpp>
#endif

int main(){
#ifdef DEBUG
	cout << "--- Input ---" << endl;
#endif
	ll N;
	cin >> N;

#ifdef DEBUG
	cout << "--- Logic ---" << endl;
#endif
	vl A;
	rep1(a,9){
		reps(b,a+1,10){
			ll x=10*a+b;
			A.push_back(x);
		}
	}
	sort(A.begin(),A.end());
#ifdef DEBUG
	cout<<A;
#endif
	ll x=(N-1)/36;
	ll y=(N-1)%36;
	string ans=to_string(A.at(y));
	char se=ans.back();
	rep(i,x){
		ans+=se;
	}
#ifdef DEBUG
	cout << "--- Answer ---" << endl;
#endif
	cout<<ans<<endl;
}
//cout << fixed << setprecision(9);