#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <iostream>
#include <string>
#include <vector>

using namespace std;
int dp[2][50010],inf = 1000000000;
int di[50010];
int main(){
    int i,j,k,n,a,b; cin >> n >> a >> b;
    string s; cin >> s;
    for(i=0;i<n;i++){
        for(j=0;j<2;j++) dp[j][i] = -inf;
    }
    for(i=0;i<=n;i++) di[i] = i/b;
    dp[0][0] = 0;
    string t;
    for(i=0;i<n;i++){
        if(i + 2<n && s.substr(i,3)=="con"){
           i += 2;
           t.push_back('y'); 
        }else{
            t.push_back('x');
        }
    }
    vector<pair<char,int>> v;
    for(i=0;i<t.size();i++){
        if(v.size()==0 || v.back().first!=t[i]) v.push_back({t[i],1});
        else v.back().second++;
    }
    int mx = n/3;
    for(i=0;i<v.size();i++){
        if(v[i].first=='x') continue;
        for(j=0;j<=mx;j++){
            if(dp[0][j]<0) continue;
            int lim = min(v[i].second/a,mx - j);
            for(k=0;k<=lim;k++){
                dp[1][j + k] = max(dp[1][j + k],dp[0][j] + di[v[i].second - a*k]);
            }
        }
        swap(dp[0],dp[1]);
    }
    int ans = 0;
    for(j=0;j<=mx;j++){
        if(dp[0][j]==j - 1) ans = max(ans,2*j - 1);
        else if(dp[0][j]>=j) ans = max(ans,2*j);
    }
    cout << ans << "\n";
}