#include <iostream>

using namespace std;

int size_str(string s){
    int sum = 0;
    for (int i = 0; i < s.length(); ++i){
        sum += s[i] - '0';
    }
    return sum;
}

int main() {
    string s;
    cin >> s;

    int sum = size_str(s);

    for(int i = 0; i < s.length(); ++i){
        string s1 = s;
        while (s1[i] < '9') {
            s1[i]++;
            if (s1[i] <= '6') {
                continue;
            }
            int sum1 = size_str(s1);
            if (sum1 % 3 == 0) {
                cout << s1;
                return 0;
            }
        }
    }
    cout << sum;
    return 0;
}