import java.util.*;
public class Main {
static String check(String s) {
char[] arr = s.toCharArray();
int[] charcount = new int[26];
for (char c : arr) {
charcount[c - 97]++;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < charcount.length; i++) {
if (charcount[i] != 0) {
char ch = (char) (i + 97);
sb.append(ch);
if (charcount[i] != 1) {
sb.append(charcount[i]);
}
}
}
return sb.toString();
}
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
String s = sc.next();
String res = check(s);
System.out.println(res);
}
}