CF sample 2

#include<bits/stdc++.h>
using namespace std;
int main() {
    //freopen("input.txt", "r", stdin);
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    string s;
    int one = 0, two = 0, three = 0, i;
    cin >> s;
    for (i = 0; i < s.length(); i = i + 2) {
        switch (s[i]) {
        case '1':
            ++one;
            break;
        case '2':
            ++two;
            break;
        case '3':
            ++three;
            break;
        default:
            break;
        }
    }
    i = 0;
    while (one) {
        s[i] = '1';
        i += 2;
        --one;
    }
    while (two) {
        s[i] = '2';
        i += 2;
        --two;
    }
    while (three) {
        s[i] = '3';
        i += 2;
        --three;
    }
    cout << s << "\n";
    return 0;
}