# Enter your code here. Read input from STDIN. Print output to STDOUT

n = int(raw_input())
s = list(str(raw_input()))

level = 0
count = 0
for c in s:
    if level == 0 and c == 'D':
        count += 1
    
    if c == 'D':
        level += 1
    else:
        level -= 1

print count