n, A, B = map(int, input().split())
s = input().strip()

runs = []
current_run = 0
i = 0

while i <= len(s) - 3:
    if s[i] == 'c' and s[i+1] == 'o' and s[i+2] == 'n':
        current_run += 1
        i += 3
    else:
        if current_run > 0:
            runs.append(current_run)
            current_run = 0
        i += 1

if current_run > 0:
    runs.append(current_run)

total_steps = 0

for m in runs:
    current = m
    steps = 0
    turn = A
    while True:
        if current >= turn:
            steps += 1
            current -= turn
            turn = B if turn == A else A
        else:
            break
    total_steps += steps

print(total_steps)