Codeforces - 339A

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

int main()
{
    string word;
    cin >> word;
    int length = word.size();
    for (int i = 0 ; i < length ; i+=2){
        for (int j = 0 ; j < length - i - 2 ; j+=2){
            if (word[j] > word[j+2]){
                swap(word[j],word[j+2]);
            }
        }
    }
    cout << word << endl;
    return 0;
}