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()
tot = sum(lst)

c = 0
d = 0
cnt = {}
for l in lst:
    c += l // a
    l %= a
    d += l // b
    l %= b
    cnt[l] = cnt.get(l, 0) + 1

def ok(x):
    aa = (x + 1) // 2
    bb = x - aa

    ab = aa * a + bb * b
    if ab > tot:
        return False
    
    if c < aa:
        return False
    elif d >= bb:
        return True

    cc = c - aa
    dd = bb - d

    hq = []
    for k, v in cnt.items():
        heappush(hq, (-k, v))
    
    while cc > 0:
        k, v = heappop(hq)
        k *= -1
        if cc > v:
            cc -= v
            k += a
            dd -= k // b * v
            k %= b
            heappush(hq, (-k, v))
        else:
            v = cc
            cc -= v
            k += a
            dd -= k // b * v
            break


    return dd <= 0



l = 0
r = n + 1
while r - l > 1:
    mid = (l + r) // 2
    if ok(mid):
        l = mid
    else:
        r = mid
print(l)