include <bits/stdc++.h>

using namespace std; int a[10];

int main() {

long long n;
cin >> n;
while (n != 0) {
	int x = n % 10;
	a[x]++;
	n = n / 10;
}
for (int i = 1; i <= 9; i++) {
	if (a[i] != 0) {
		cout << i;
		a[i]--;
		break;
	}
}
for (int i = 0; i <= 9; i++) {
	if (a[i] != 0) {
		while (a[i]--) {
			cout << i;
		}
	}
}

return 0;

}