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

bool judge(const std::string& s, int kr, int kb) {
    int n = s.length();
    for (int i = 0; i < n; ++i) {
        switch (s[i]) {
            case 'R':
                if (i + kr < n && s[i + kr] == 'R') return false;
                break;
            case 'B':
                if (i + kb < n && s[i + kb] == 'B') return false;
                break;
        }
    }
    return true;
}

void solve() {
    int kr, kb;
    std::string s;
    std::cin >> kr >> kb >> s;

    int ans = 0;
    for (int b = 0; b < (1 << 20); ++b) {
        std::string t;
        int itr = 0;
        for (char c : s) {
            if (c == 'R' || c == 'B') {
                if ((b >> itr++) & 1) continue;
            }
            t.push_back(c);
        }

        if (!judge(t, kr, kb)) continue;
        ans = std::max(ans, (int)t.length());
    }

    std::cout << ans << "\n";
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}