#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <queue>
#include <atcoder/modint>

using namespace std;
using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;
#define rep(i,n) for(int i=0; i<(int)(n); i++)

using Modint = atcoder::static_modint<998244353>;


int main(){
    int N,A,B; cin >> N >> A >> B;
    string S; cin >> S;

    vector<int> ConCon = {0};
    while(S.size() >= 3){
        if(S.substr(S.size() - 3) == "con"){
            S.resize(S.size() - 3);
            ConCon.back()++;
            continue;
        }
        if(ConCon.back() != 0) ConCon.push_back(0);
        S.pop_back();
    }
    if(ConCon.back() == 0) ConCon.pop_back();
    
    vector<int> Q(N/3/A+1, -1001001001);
    Q[0] = 0;
    for(int s : ConCon){
        vector<int> bV;
        for(int a=0; a*A<=s; a++) bV.push_back((s-a*A)/B);
        for(int q=Q.size()-1; q>=0; q--){
            int tmp = -1001001001;
            for(int a=min((int)bV.size()-1,q); a>=0; a--) tmp = max(tmp, Q[q-a] + bV[a]);
            Q[q] = tmp;
        }
    }

    int ans = 0;
    rep(i,Q.size()) if(Q[i] >= 0) ans = max(ans, min(i*2,Q[i]*2+1));
    cout << ans << '\n';
    return 0;
}


struct ios_do_not_sync{
    ios_do_not_sync(){
        std::ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
    }
} ios_do_not_sync_instance;