n,a,b=map(int,input().split())
s=input()

c=[]
for i in s:
  c.append(i)
  if len(c)>=3 and c[-3]+c[-2]+c[-1]=='con':
    c.pop()
    c.pop()
    c.pop()
    c.append('!')

c.append('a')
d=[]
tmp=0
for i in c:
  if i=='!':
    tmp+=1
  else:
    if tmp!=0:
      d.append(tmp)
    tmp=0

m=n//3+10
dp=[-10**9]*m
dp[0]=0
mx=0
for i in d:
  ndp=dp.copy()
  tmp=0
  while True:
    c1=tmp
    c2=(i-a*tmp)//b
    if c2<0:
      break
    for j in range(mx+1):
      ndp[j+c1]=max(ndp[j+c1],dp[j]+c2)
    tmp+=1
  mx+=c1
  dp=ndp

ans=0
#print(dp)
for i in range(1,m):
  if dp[i]>=i-1:
    ans=max(2*i-1,ans)
  if dp[i]>=i:
    ans=max(ans,2*i)

print(ans)