Ram has a strange habit of playing with strings. He has formulated the density of strings now. What is the density of strings? The density of a word is defined as the absolute difference between the capital and the smaller letters. The density of an entire line/string would be defined as the maximum such density of all words of a text.

Input First line is the length of the string. Second line contains the text

Output:- density of the text.

Constraints Lenght of the text 1<=n<=200.