import java.util.*;
import java.util.stream.IntStream;
public class Main{
static final int MAX_CHAR = 26;
static void sortString(String str) {
int letters[] = new int[MAX_CHAR];
for (char x : str.toCharArray()) {
letters[x - 'a']++;
}
IntStream.range(0, letters.length).forEach(i -> {
IntStream.range(0, letters[i]).forEach(ch -> {
System.out.print((char) (i + 'a'));
});
});
}
// Driver program to test above function
public static void main(String[] args) {
sortString("geeksforgeeks");
}
}