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

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

steps = 0
current_step = 1

while True:
    k = A if current_step % 2 == 1 else B
    found = False
    for i in range(len(runs)):
        if runs[i] >= k:
            runs[i] -= k
            if runs[i] == 0:
                del runs[i]
            steps += 1
            current_step += 1
            found = True
            break
    if not found:
        break

print(steps)