#include <iostream>
using namespace std;
int v[10];
int main(){ long long n; cin >> n; while (n) { v[n%10]++; n/=10; } for (int i = 1; i<=9; i++) if (v[i]) { cout << i; v[i]--; break; } while (v[0]) { cout << 0; v[0]--; } for (int i = 1; i<=9; i++) { while (v[i]) { cout << i; v[i]--; } }}