n = int(input())
s = input().strip()

if n == 0:
    print(0)
    exit()

color_changes = 0
for i in range(1, n):
    if s[i] != s[i-1]:
        color_changes += 1

count = 0
for i in range(2, n):
    if s[i] == s[i-2] and s[i] != s[i-1]:
        count += 1

ans = (color_changes + 1) - count
print(ans)