#include<bits/stdc++.h>
using namespace std;

string hieu(string s,  int k)
{
     string t = to_string(k);
     int i = s.size() - 1, j = t.size() - 1, nho = 0;

     while(j >= 0 || nho)
     {
          int x = s[i] - '0' - nho;
          int y = (j >= 0 ? t[j] - '0' : 0);

          if(x < y){
               x += 10;
               nho = 1;
          }
          else nho = 0;

          s[i] = char(x - y + '0');
          i--;
          j--;
     }

     while(i >= 0)
     {
          int x = s[i] - '0' - nho;
          if(x < 0){
               s[i] = '9';
               nho = 1;
          }
          else{
               s[i] = char(x + '0');
               nho = 0;
          }
          i--;
     }

     int p = 0;
     while(p + 1 < s.size() && s[p] == '0') p++;
     return s.substr(p);
}

bool check(string s, int k){
     string t = to_string(k);
     if(s.size() < t.size()) return true;
     else if(s.size() == t.size()){
          for(int i = 0; i < s.size(); i++){
               if(t[i] > s[i]) return true;
          }
     }

     return false;
}
int main()
{
     ios_base::sync_with_stdio(0);
     cout.tie(0);cin.tie(0);

     string s; cin >> s;
     for(int k = 9 * 100; k >= 1; k--){
          if(check(s, k)) continue;
          string m = hieu(s, k);

          int sum = 0;
          for(int i = 0; i < m.size(); i++) sum += m[i] - '0';

          if(sum == k){
               cout << m;
               return 0;
          }
     }
     cout << 0;


}