import bisect

n, A, B = map(int, input().split())
S = input().strip()

runs = []
i = 0
while i <= len(S) - 3:
    if S[i] == 'c' and S[i+1] == 'o' and S[i+2] == 'n':
        cnt = 0
        while i <= len(S) - 3 and S[i] == 'c' and S[i+1] == 'o' and S[i+2] == 'n':
            cnt += 1
            i += 3
        runs.append(cnt)
    else:
        i += 1

runs.sort()

count = 0
step = 1
current_runs = runs.copy()

while True:
    if step % 2 == 1:
        X = A
    else:
        X = B

    idx = bisect.bisect_left(current_runs, X)
    if idx < len(current_runs):
        run = current_runs.pop(idx)
        remaining = run - X
        if remaining > 0:
            bisect.insort(current_runs, remaining)
        count += 1
        step += 1
    else:
        break

print(count)