Given an integer len, count the number of different good strings that have a length of exactly len. A good string is a string for which the following conditions are true:

A good string contains only lowercase English letters. Each character in a good string is unique. Exactly one character in a good string is lexicographically greater than the character that precedes it. Example

For len = 2, the output should be goodStringsCount(len) = 325.

If the first symbol is 'a', there are 25 possible good strings: "ab", "ac", ... If the first symbol is 'b', there are 24 possible good strings: "bc", "bd", ... ... If the first symbol is 'z', there are 0 possible good strings because there is no character that is lexicographically greater. There are 25 + 24 + 23 + ... + 0 = 325 good strings that have a length of 2.

For len = 1, the output should be goodStringsCount(len) = 0.

The 3rd rule for good strings can't be true if there is only one character in the string.

Input/Output

[time limit] 4000ms (py3) [input] integer len

The length of good strings that you're looking for.

Guaranteed constraints: 1 ≤ len ≤ 9.

[output] integer

The number of different good strings with a length of exactly len.



In [2]:

    
def goodStringsCount(len):
    if len == 0:
        return 0
    else:
        pass
def temp(val):
    if val > 0:
        return val + temp(val -1)
    else: 
        return 0



In [13]:

    
temp(49)









    Out[13]:





1225