fn run() {
    input! {
        n: usize,
        a: usize,
        b: usize,
        s: bytes,
    }
    let con = [b'c', b'o', b'n'];
    let mut cnt = vec![];
    let mut x = 0;
    while x < s.len() {
        let c = s[x..].chunks_exact(3).take_while(|s| s == &con).count();
        if c > 0 {
            cnt.push(c);
            x += 3 * c;
        } else {
            x += 1;
        }
    }
    let inf = std::i32::MAX / 2;
    let mut dp = vec![0i32];
    for c in cnt {
        let mut next = vec![-inf; dp.len() + c / a];
        for i in 0..=(c / a) {
            let y = ((c - a * i) / b) as i32;
            for (next, dp) in next[i..].iter_mut().zip(dp.iter()).filter(|p| *p.1 != -inf) {
                *next = std::cmp::max(*next, *dp + y);
            }
        }
        dp = next;
    }
    let mut ans = 0;
    for (i, dp) in dp.iter().enumerate() {
        if *dp < 0 {
            continue;
        }
        let y = *dp as usize;
        if y < i {
            ans = ans.max(2 * y + 1);
        } else {
            ans = ans.max(2 * i);
        }
    }
    println!("{}", ans);
}

fn main() {
    run();
}

// ---------- begin input macro ----------
// reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
#[macro_export]
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

#[macro_export]
macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

#[macro_export]
macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}
// ---------- end input macro ----------