# You are given a license key represented as a string S which consists only alphanumeric character and dashes. The string is separated into N+1 groups by N dashes.
#
# Given a number K, we would want to reformat the strings such that each group contains exactly K characters, except for the first group which could be shorter than K, but still must contain at least one character. Furthermore, there must be a dash inserted between two groups and all lowercase letters should be converted to uppercase.
#
# Given a non-empty string S and a number K, format the string according to the rules described above.
#
# Example 1:
# Input: S = "5F3Z-2e-9-w", K = 4
#
# Output: "5F3Z-2E9W"
#
# Explanation: The string S has been split into two parts, each part has 4 characters.
# Note that the two extra dashes are not needed and can be removed.
# Example 2:
# Input: S = "2-5g-3-J", K = 2
#
# Output: "2-5G-3J"
#
# Explanation: The string S has been split into three parts, each part has 2 characters except the first part as it could be shorter as mentioned above.
# Note:
# The length of string S will not exceed 12,000, and K is a positive integer.
# String S consists only of alphanumerical characters (a-z and/or A-Z and/or 0-9) and dashes(-).
# String S is non-empty.

def licenseKeyFormatting(S, K):
    capital_s = ""
    for char in S:
        capital_s += (char.upper())
    license_key_arr = capital_s.split("-")
    joined_str = ''.join(license_key_arr)
    final_str = ""

    for i in range(len(joined_str) - 1, -1, -1):
        if i != 0 and (len(joined_str) - i) % K == 0:
            final_str += joined_str[i]
            final_str += '-'
        else:
            final_str += joined_str[i]

    return (final_str[::-1])




print licenseKeyFormatting("5F3Z-2e-9-w", 4)
print licenseKeyFormatting("2-5g-3-J", 2)
