# https://yukicoder.me/problems/no/2076

       

def main():
    N, A, B = map(int, input().split())
    S = input()

    S = S.replace("con", "_")
    array = []
    prev = False
    for s in S:
        if s == "_":
            if not prev:
                prev = True
                array.append(1)
            else:
                array[-1] += 1
        else:
            prev = False
    
    count = sum(array)
    a_max = (count // A) + (1 if count % A > 0 else 0)

    dp = [-1] * (a_max + 1)
    dp[0] = 0
    for n in array:
        new_dp = [-1] * (a_max +1)

        n_a = 0
        while A * n_a <= n:
            b = n - A * n_a
            b //= B
            for v in range(a_max + 1):
                if dp[v] == -1:
                    break

                if v + n_a > a_max:
                    break

                new_dp[v + n_a] = max(new_dp[v + n_a], dp[v] + b)
            n_a += 1
        dp = new_dp
    answer = 0
    for a in range(a_max + 1):
        max_b = dp[a]
        if max_b == -1:
            continue
        
        v = min(max_b, a)
        if a > v:
            ans = 2 * v + 1

        else:
            ans = 2 * v
        answer = max(answer, ans)
    print(answer)

            




        








if __name__ == "__main__":
    main()