n,a,b = map(int,input().split())
s = input()
s = s.replace("con", "X")
t = []
for i,c in enumerate(s):
  if c == "X":
    if i == 0:
      t.append(1)
    else:
      if s[i-1] == "X":
        t[-1] += 1
      else:
        t.append(1)
jmx = int(n/6+1)
dp = [-100000000]*(jmx+1)
dp[0] = 0
for i in range(1, len(t)+1):
  ti = t[i-1]
  kmx = ti//a
  new = [-1000000]*(jmx+1)
  for j in range(jmx+1):
    for k in range(kmx+1):
      if j + k > jmx: continue
      new[j+k] = max(dp[j] + (ti-k*a)//b, new[j+k], dp[j+k])
  dp = new
ans = 0
for i in range(0,jmx+1):
  if dp[i] >= i-1:
    ans = max(i+i-1, ans)
  if dp[i] >= i:
    ans = max(ans, i+i)

print(ans)