from itertools import groupby



eval(input())

print((sum(map(bool, groupby(eval(input()))))))

from itertools import groupby



eval(input())

print((sum(1 for _ in groupby(eval(input())))))

from itertools import groupby

eval(input())
print((sum(map(bool, groupby(eval(input()))))))

from itertools import groupby

eval(input())
print((sum(1 for _ in groupby(eval(input())))))

-print((sum(map(bool, groupby(eval(input())))))) +print((sum(1 for _ in groupby(eval(input())))))