#include <bits/stdc++.h>
using namespace std;
#define pll pair<int, int>
#define plll pair<int, pll>
#define tr cout << "-----------------" << '\n';
#define ll int
#define nmax 3000007
#define mmax 2007
#define pb push_back
const int mod = 1e9 + 7;
const int oo = 1e17;
const int base = 41;
const int dx[] = {0, 0, 1, -1};
const int dy[] = {1, -1, 0, 0};
long long a[nmax];
long long tcs(long long n)
{
    long long tong = 0;
    while(n > 0)
    {
        tong += n % 10;
        n /= 10;
    }
    return tong;
}
signed main()
{
    cin.tie(0)->sync_with_stdio(0);
    long long n;
    cin >> n;
    long long tong = 0;
    long long sus = tcs(n);
    string s = "";
    while(sus > 0)
    {
        if(sus > 9)
        {
            s += '9';
            sus -= 9;
        }
        else{
            s += '0' + sus;
            reverse(s.begin(), s.end());
            cout << s;
            return 0;
        }
    }
}