N, A, B = map(int, input().split())
S = str(input())
rle = []
concnt = 0
now_idx = 0
while True:
    if now_idx >= N - 2:
        if concnt >= 1:
            rle.append(concnt)
        break
    elif S[now_idx:(now_idx + 3)] == 'con':
        now_idx += 3
        concnt += 1
    else:
        now_idx += 1
        if concnt >= 1:
            rle.append(concnt)
        concnt = 0

INF = -50000
dp1 = [INF for _ in range(8338)]
dp2 = [INF for _ in range(8338)]
dp1[0] = 0
for i in range(len(rle)):
    for j in range(8338):
        for k in range(rle[i] // A + 1):
            if j + k >= 8338:
                continue
            dp2[j + k] = max(dp2[j + k], dp1[j] + (rle[i] - A * k) // B)
    for j in range(8338):
        dp1[j] = dp2[j]
        dp2[j] = INF
    #print(dp1[0:5])
ans = 0
for j in range(8338):
    if dp1[j] >= j - 1:
        ans = max(ans, 2 * j - 1)
    if dp1[j] >= j:
        ans = max(ans, 2 * j)
print(ans)