Bracket operator, negative index

LETTER = STRING[J]

if J is negative:

J=-1 yields the last letter of STRING,

J=-2 yields the second to last letter, etc

Example:

name = "Sandy"
firstLetter=name[-5]
secondLetter=name[-4]
lastLetter=name[-1]
print firstLetter, secondLetter, lastLetter

prints:

S a y