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

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

runs = []
current = s[0]
runs.append(current)
for c in s[1:]:
    if c != runs[-1]:
        runs.append(c)

count = 0
for i in range(len(runs) - 2):
    if runs[i] == runs[i+2] and runs[i+1] != runs[i]:
        count += 1

minimal_operations = len(runs) - count
print(minimal_operations)