-- Enter your code here. Read input from STDIN. Print output to STDOUT
countValleys [] _ = 0
countValleys (x:xs) level
    | x == 'U' && level == -1 = 1 + countValleys xs (level + 1)
    | x == 'D' = countValleys xs (level - 1)
    | x == 'U' = countValleys xs (level + 1)
    
    
main = do
    q <- getLine
    steps <- getLine
    print $ countValleys steps 0