#line 2 "library/template.hpp"
// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>
using namespace std;
// https://xn--kst.jp/blog/2019/08/29/cpp-comp/
// debug methods
// usage: debug(x,y);
#define CHOOSE(a) CHOOSE2 a
#define CHOOSE2(a0, a1, a2, a3, a4, x, ...) x
#define debug_1(x1) cout << #x1 << ": " << x1 << endl
#define debug_2(x1, x2)                                                        \
    cout << #x1 << ": " << x1 << ", " #x2 << ": " << x2 << endl
#define debug_3(x1, x2, x3)                                                    \
    cout << #x1 << ": " << x1 << ", " #x2 << ": " << x2 << ", " #x3 << ": "    \
         << x3 << endl
#define debug_4(x1, x2, x3, x4)                                                \
    cout << #x1 << ": " << x1 << ", " #x2 << ": " << x2 << ", " #x3 << ": "    \
         << x3 << ", " #x4 << ": " << x4 << endl
#define debug_5(x1, x2, x3, x4, x5)                                            \
    cout << #x1 << ": " << x1 << ", " #x2 << ": " << x2 << ", " #x3 << ": "    \
         << x3 << ", " #x4 << ": " << x4 << ", " #x5 << ": " << x5 << endl
#ifdef LOCAL
#define debug(...)                                                             \
    CHOOSE((__VA_ARGS__, debug_5, debug_4, debug_3, debug_2, debug_1, ~))      \
    (__VA_ARGS__)
#else
#define debug(...)
#endif

using ll = long long;
using vl = vector<ll>;
using Graph = vector<vector<ll>>;
using P = pair<ll, ll>;
#define all(v) v.begin(), v.end()
template <typename T> inline bool chmax(T &a, T b) {
    return ((a < b) ? (a = b, true) : (false));
}
template <typename T> inline bool chmin(T &a, T b) {
    return ((a > b) ? (a = b, true) : (false));
}
#define rep1(i, n) for(ll i = 1; i <= ((ll)n); ++i)
// https://trap.jp/post/1224/
template <class... T> constexpr auto min(T... a) {
    return min(initializer_list<common_type_t<T...>>{a...});
}
template <class... T> constexpr auto max(T... a) {
    return max(initializer_list<common_type_t<T...>>{a...});
}
template <class... T> void input(T &...a) {
    (cin >> ... >> a);
}
template <class T> void input(vector<T> &a) {
    for(T &x : a)
        cin >> x;
}
void print() {
    cout << '\n';
}
template <class T, class... Ts> void print(const T &a, const Ts &...b) {
    cout << a;
    (cout << ... << (cout << ' ', b));
    cout << '\n';
}
template <class T> void print(vector<T> x) {
    if(x.size()) {
        for(ll i = 0; i < x.size(); i++) {
            cout << x[i] << " \n"[i + 1 == x.size()];
        }
    }
}
#define INT(...)                                                               \
    int __VA_ARGS__;                                                           \
    input(__VA_ARGS__)
#define LL(...)                                                                \
    long long __VA_ARGS__;                                                     \
    input(__VA_ARGS__)
#define STR(...)                                                               \
    string __VA_ARGS__;                                                        \
    input(__VA_ARGS__)
#define REP1(a) for(int i = 0; i < a; i++)
#define REP2(i, a) for(int i = 0; i < a; i++)
#define REP3(i, a, b) for(int i = a; i < b; i++)
#define REP4(i, a, b, c) for(int i = a; i < b; i += c)
#define overload4(a, b, c, d, e, ...) e
#define rep(...) overload4(__VA_ARGS__, REP4, REP3, REP2, REP1)(__VA_ARGS__)

ll inf = 3e18;
vl dx = {1, -1, 0, 0};
vl dy = {0, 0, 1, -1};
#line 2 "yukicoder/515/a.cpp"
#include <atcoder/modint>
using namespace atcoder;
using mint = modint998244353;
// #include <atcoder/segtree>
void solve() {
    LL(n);
    STR(s);

    vector dp(n + 1, vector(3, mint(0)));
    // L,R,U
    dp[0][2] = 1;
    rep(i, n) {
        if(s[i] == 'L') {
            dp[i + 1][0] = dp[i][0] + dp[i][2];
        } else if(s[i] == 'R') {
            dp[i + 1][1] = dp[i][1] + dp[i][2] + dp[i][0];
        } else if(s[i] == 'U') {
            dp[i + 1][2] = dp[i][0] + dp[i][1] + dp[i][2];
        } else {
            dp[i + 1][0] = dp[i][0] + dp[i][2];
            dp[i + 1][1] = dp[i][1] + dp[i][2] + dp[i][0];
            dp[i + 1][2] = dp[i][0] + dp[i][1] + dp[i][2];
        }
    }
    // rep1(i,n){
    //     rep(j,3)cout << dp[i][j].val() << " ";
    //     cout << endl;
    // }
    mint ans = dp[n][0] + dp[n][1] + dp[n][2];
    print(ans.val());
}
int main() {
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    cout << std::setprecision(16);
    int t = 1;
    // cin >> t;
    rep(_, t) {
        solve();
    }
}