def preprocess(s):
    runs = []
    n = len(s)
    i = 0
    while i < n:
        if i <= n - 3 and s[i] == 'c' and s[i+1] == 'o' and s[i+2] == 'n':
            count = 0
            j = i
            while j <= n - 3 and s[j] == 'c' and s[j+1] == 'o' and s[j+2] == 'n':
                count += 1
                j += 3
            runs.append(('con', count))
            i = j
        else:
            runs.append(('other', 1))
            i += 1
    return runs

def main():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    N = int(input[idx])
    idx +=1
    A = int(input[idx])
    idx +=1
    B = int(input[idx])
    idx +=1
    S = input[idx]
    idx +=1
    
    runs = preprocess(S)
    operations = 0
    step = 1
    
    while True:
        K = A if (step % 2 == 1) else B
        found = False
        for i in range(len(runs)):
            typ, cnt = runs[i]
            if typ == 'con' and cnt >= K:
                # Replace this run
                runs.pop(i)
                # Insert 'other' run of 4
                runs.insert(i, ('other', 4))
                if cnt > K:
                    # Insert remaining 'con' run
                    runs.insert(i+1, ('con', cnt - K))
                operations += 1
                found = True
                break
        if not found:
            break
        step += 1
    print(operations)

if __name__ == "__main__":
    main()