#![allow(non_snake_case)]
#![allow(unused_imports)]
#![allow(unused_macros)]
#![allow(clippy::needless_range_loop)]
#![allow(clippy::comparison_chain)]
#![allow(clippy::nonminimal_bool)]
#![allow(clippy::neg_multiply)]
#![allow(dead_code)]
#![allow(clippy::collapsible_else_if)]
use proconio::{
    fastout, input, input_interactive,
    marker::{Chars, Usize1},
};
use std::cmp::Reverse;
use std::collections::BinaryHeap;
use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet, VecDeque};
use std::mem::swap;

//const MOD: usize = 1e9 as usize + 7;
const MOD: usize = 998244353;
// const MOD: usize = 2147483647;

#[macro_export]
macro_rules! max {
    ($x: expr) => ($x);
    ($x: expr, $( $y: expr ),+) => {
        std::cmp::max($x, max!($( $y ),+))
    }
}
#[macro_export]
macro_rules! min {
    ($x: expr) => ($x);
    ($x: expr, $( $y: expr ),+) => {
        std::cmp::min($x, min!($( $y ),+))
    }
}
fn main() {
    input! {
        N:usize,
        S:Chars,
    }
    let _mod: usize = 998244353;
    let mut dp = vec![vec![0; 3]; N];
    if S[0] == 'L' {
        dp[0] = vec![1, 0, 0];
    } else if S[0] == 'R' {
        dp[0] = vec![0, 1, 0];
    } else if S[0] == 'U' {
        dp[0] = vec![0, 0, 1];
    } else {
        dp[0] = vec![1, 1, 1];
    }
    if N > 1 {
        for i in 1..N {
            dp[i][0] = dp[i - 1][0] + dp[i - 1][2];
            dp[i][1] = dp[i - 1][0] + dp[i - 1][1] + dp[i - 1][2];
            dp[i][2] = dp[i - 1][0] + dp[i - 1][1] + dp[i - 1][2];
            dp[i][0] %= _mod;
            dp[i][1] %= _mod;
            dp[i][2] %= _mod;
            if S[i] == 'L' {
                dp[i][1] = 0;
                dp[i][2] = 0;
            } else if S[i] == 'R' {
                dp[i][0] = 0;
                dp[i][2] = 0;
            } else if S[i] == 'U' {
                dp[i][0] = 0;
                dp[i][1] = 0;
            }
        }
    }
    let mut ans = dp[N - 1][0] + dp[N - 1][1] + dp[N - 1][2];
    ans %= _mod;
    println!("{}", ans);
}