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

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

total = 0
for m in runs:
    ab = A + B
    full = m // ab
    rem = m % ab
    total += full * 2 + (1 if rem >= A else 0)

print(total)