To be proper pascal case a word with no digits allowed and with upto 3 upper case letters, a word:

• MUST start with an upper case alphabet (A through Z)
• MUST have no digits (0 - 9)
• MUST have no spaces, punctuation or special characters
• CAN have at most 3 uppercase alphabets in a row
• CAN end in an uppercase alphabet

Notable examples

• IOStream is valid pascal case with no digits allowed and with upto 3 upper case letters
• StreamIO is valid pascal case with no digits allowed and with upto 3 upper case letters
• IOStream is valid pascal case with no digits allowed and with upto 3 upper case letters
• DeviceID is valid pascal case with no digits allowed and with upto 3 upper case letters
• AwsVPC is valid pascal case with no digits allowed and with upto 3 upper case letters
• DeviceSNS is valid pascal case with no digits allowed and with upto 3 upper case letters
• CreateAMode is valid pascal case with no digits allowed and with upto 3 upper case letters
• CreateBMode is valid pascal case with no digits allowed and with upto 3 upper case letters
• ABCabcABCabc is valid pascal case with no digits allowed and with upto 3 upper case letters
• ABCabcABCabcA is valid pascal case with no digits allowed and with upto 3 upper case letters