#include <bits/stdc++.h>

using namespace std;

bool c;

int sumdigits(long long n)
{
    int sum=0;
    while(n)
    {
        sum+=n%10;
        n/=10;
    }
    return sum;
}

int main()
{
#ifdef ONLINE_JUDGE
    freopen("cool.in", "r", stdin);
    freopen("cool.out", "w", stdout);
#endif
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);

    /*long long l,r;
    long long n;
    cin>>l>>r;
    for(int j=l; j<=r; j++)
    {
        n=j;
        c=false;
        for(int i=2*n; i>=1; i--)
        {
        if(i-sumdigits(i)==n)
        {
            cout<<n<<": "<<i<<endl;
            c=true;
            break;
        }
        }
        if(c==false)cout<<n<<": "<<-1<<endl;
    }*/
    long long n;
    cin>>n;
    if(n%9==0)
    {
        for(int i=2*n; i>=1; i--)
        {
        if(i-sumdigits(i)==n)
        {
            cout<<i<<endl;
            return 0;
        }
        }
        cout<<-1<<endl;
    }else cout<<-1<<endl;
    return 0;
}