from heapq import *

n, a, b = map(int, input().split())
S = input()
S = S.replace("con", "*")
lst = []
row = 0
for s in S:
    if s == "*":
        row += 1
    else:
        if row != 0:
            lst.append(row)
        row = 0
if row != 0:
    lst.append(row)
lst.sort()

aa = 0
bb = 0
C = []
for l in lst:
    aa += l // a
    l %= a
    bb += l // b
    l %= b
    C.append(-l)

def f(a, b):
    if a > b:
        return 2 * b + 1
    else:
        return 2 * a
heapify(C)

ans = f(aa, bb)
for i in range(aa - 1, -1, -1):
    c = -heappop(C)
    c += a
    bb += c // b
    c %= b
    heappush(C, -c)
    ans = max(ans, f(i, bb))


print(ans)