from __future__ import print_function
# Python program for counting sort
 
# This is the main function that sort the given string arr[] in
# in the alphabetical order 
def countSort(arr):
 
    # The output character array that will have sorted arr
    output = [0 for i in range(256)]
 
    # Create a count array to store count of inidividul
    # characters and initialize count array as 0
    count = [0 for i in range(256)]
 
    # For storing the resulting answer since the 
    # string is immutable
    ans = ["" for _ in arr]
 
    # Store count of each character
    for i in arr:
        count[ord(i)] += 1
 
    # Change count[i] so that count[i] now contains actual
    # position of this character in output array
    for i in range(256):
        count[i] += count[i-1]
 
    # Build the output character array
    for i in range(len(arr)):
        output[count[ord(arr[i])]-1] = arr[i]
        count[ord(arr[i])] -= 1
 
    # Copy the output array to arr, so that arr now
    # contains sorted characters
    for i in range(len(arr)):
        ans[i] = output[i]
    return ans 
 
# Driver program to test above function
arr = "thisisthestring"
ans = countSort(arr)
print ("Sorted string array is %s"  %("".join(ans)))