n, a, b = map(int, input().split())
s = input().strip()

runs = []
i = 0
while i <= len(s) - 3:
    if s[i:i+3] == 'con':
        count = 1
        i += 3
        while i <= len(s) - 3 and s[i:i+3] == 'con':
            count += 1
            i += 3
        runs.append(count)
    else:
        i += 1

total = 0
for x in runs:
    pair = a + b
    if pair == 0:
        continue  # but a and b are >=1, so this is impossible
    full_pairs = x // pair
    total += full_pairs * 2
    rem = x % pair
    if rem >= a:
        total += 1

print(total)