#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();

    int t = 0;
    if(A < B){ swap(A, B); t = 1; }

    priority_queue<pair<int,int>> ConQue;
    rep(i,ConCon.size()) ConQue.push({ ConCon[i] % A, i });
    int SumConA = 0;
    int SumConB = 0;
    for(int a : ConCon) SumConA += a / A;
    int ans = min(SumConA * 2 + t, SumConB * 2 + 1 - t);
    while(ConQue.size()){
        auto [ a, i ] = ConQue.top();
        ConQue.pop();
        if(ConCon[i] < B) continue;
        SumConA -= ConCon[i] / A;
        ConCon[i] -= B;
        SumConB++;
        SumConA += ConCon[i] / A;
        ConQue.push({ ConCon[i] % A, i });
        ans = max(ans, min(SumConA * 2 + t, SumConB * 2 + 1 - t));
    }

    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;