#include <bits/stdc++.h>
using namespace std;
template <typename T> using min_priority_queue = priority_queue<T,vector<T>,greater<T>>;

random_device seed_gen;
mt19937 engine(seed_gen());

int64_t get_time(){
    struct::timespec t;
    clock_gettime(CLOCK_MONOTONIC, &t);
    return t.tv_sec * int64_t(1'000'000'000) + t.tv_nsec;
}

template<typename T>
void invec(vector<T> &v){
    for(auto &i : v) cin >> i;
    return;
}

template<typename T>
void outvec(vector<T> &v, string s = " "){
    bool b = false;
    for(auto i : v){
        if(b) cout << s;
        else b = true;
        cout << i;
    }
    cout << endl;
    return;
}

template <typename T>
bool chmin(T &a, const T& b) {
    if (a > b) {
        a = b;  // aをbで更新
        return true;
    }
    return false;
}

template <typename T>
bool chmax(T &a, const T& b) {
    if (a < b) {
        a = b;  // aをbで更新
        return true;
    }
    return false;
}

template<typename T>
T pow_mod(T a, T b, T n){
    a %= n;
    if(a == 0) return 0;
    if(a == 1 || b == 0) return 1;
    if(b == 1) return a;
    T c = b/2;
    T d = b%2;
    T ac = pow_mod(a,c,n);
    T ad = pow_mod(a,d,n);
    return ac*ac%n*ad%n;
}

template <typename T>
T ex_euclid(T a, T b, T &x, T &y){
    T d = a;
    if(b != 0){
        d = ex_euclid(b, a%b, y, x);
        y -= (a/b)*x;
    }
    else{
        x = 1;
        y = 0;
    }
    //cout << a << " * " << x << " + " << b << " * " << y << " = " << d << endl;
    return d;
}

template <int64_t mod>
struct modint{
    int64_t val;

    modint(){
        val = 0;
    }

    modint(int64_t a){
        if(a <= -mod) a %= mod;
        else if(a >= mod) a %= mod;
        if(a < 0) a += mod;
        val = a;
    }

    modint inv(){
        int64_t x, k;
        int64_t d = ex_euclid(val, mod, x, k);
        assert(d == 1);
        return modint(x);
    }

    bool operator==(modint other){
        return val == other.val;
    }
    bool operator!=(modint other){
        return val != other.val;
    }

    modint operator+(modint other){
        return modint(val + other.val);
    }
    modint operator-(modint other){
        return modint(val - other.val);
    }
    modint operator*(modint other){
        return modint(val * other.val);
    }
    modint operator/(modint other){
        return modint(val * other.inv().val);
    }

    void operator+=(modint other){
        val += other.val;
        if(val >= mod) val -= mod;
    }
    void operator-=(modint other){
        val -= other.val;
        if(val < 0) val += mod;
    }
    void operator*=(modint other){
        val *= other.val;
        val %= mod;
    }
    void operator/=(modint other){
        val *= other.inv().val;
        val %= mod;
    }

    void operator++(){
        val++;
        if(val >= mod) val -= mod;
    }
    void operator--(){
        val--;
        if(val < 0) val += mod;
    }
};

template <int64_t mod>
modint<mod> pow(modint<mod> a, int64_t b){
    using mint = modint<mod>;

    if(b <= -(mod - 1)) b %= mod - 1;
    else if(b >= (mod - 1)) b %= mod - 1;
    if(b < 0) b += mod - 1;

    if(a == 0) return mint(0);
    if(b == 0) return mint(1);
    if(a == 1) return mint(1);
    if(b == 1) return a;

    mint x = pow(a, b / 2);
    mint y = pow(a, b % 2);
    return x * x * y;
}

template <int64_t mod>
pair<vector<modint<mod>>, vector<modint<mod>>> init_mod_factorial(int N){
    using mint = modint<mod>;

    vector<mint> v(N+1);
    vector<mint> v_inv(N+1);
    for(int i = 0; i <= N; i++){
        if(i == 0) v[i] = 1;
        else v[i] = v[i - 1] * i;
    }
    for(int i = N; i >= 0; i--){
        if(i == N) v_inv[i] = v[i].inv();
        else v_inv[i] = v_inv[i+1] * (i + 1);
    }

    return make_pair(v, v_inv);
}

template <int64_t mod>
modint<mod> factorial_mod(int64_t x, pair<vector<modint<mod>>, vector<modint<mod>>> &factorial_list){
    return factorial_list.first[x];
}

template <int64_t mod>
modint<mod> factorial_inv_mod(int64_t x, pair<vector<modint<mod>>, vector<modint<mod>>> &factorial_list){
    return factorial_list.second[x];
}

template <int64_t mod>
modint<mod> comb_mod(int64_t x, int64_t y, pair<vector<modint<mod>>, vector<modint<mod>>> &factorial_list){
    if(y < 0 || x < y) return modint<mod>(0);
    return factorial_list.first[x] * factorial_list.second[y] * factorial_list.second[x - y];
}

bool yn(bool b){
    if(b) cout << "Yes" << endl;
    else cout << "No" << endl;
    return b;
}

bool check_with_simple_solution;
bool calc_time;
bool random_input;
bool debug_output;
int num_of_testcase;

using ans_type = int;

void input(){
    if(num_of_testcase > 1){
    }
    if(random_input){
    }   
    else{
    }
    return;
}

void output_input(){
    return;
}

void pre_solve(){
    return;
}

ans_type solve(){
    const int64_t mod = 998244353;
    using mint = modint<mod>;

    int n; cin >> n;
    string s; cin >> s;

    vector DP(n+1, vector<mint>(3, 0));
    DP[0][0] = 1;
    for(int i = 0; i < n; i++) {
        char c = s[i];
        if(c == 'L' || c == '.') {
            DP[i+1][0] += DP[i][0] + DP[i][1];
        }
        if(c == 'U' || c == '.') {
            DP[i+1][1] += DP[i][0] + DP[i][1] + DP[i][2];
        }
        if(c == 'R' || c == '.') {
            DP[i+1][2] += DP[i][0] + DP[i][1] + DP[i][2];
        }
    }

    mint ans = DP[n][0] + DP[n][1] + DP[n][2];
    cout << ans.val << endl;
    return ans_type();
}

ans_type solve_simple(){
    return ans_type();
}

void output(ans_type ans){
    return;
}

int main(){
    ios::sync_with_stdio(false);
	cin.tie(nullptr);
    cout << fixed << setprecision(20);

    check_with_simple_solution = 0;
    calc_time = 0;
    random_input = 0;
    debug_output = 0;
    num_of_testcase = 1;
    
    if(num_of_testcase == 0) cin >> num_of_testcase;

    pre_solve();

    if(check_with_simple_solution){
        for(int i = 0; i < num_of_testcase; i++){
            if(debug_output) cout << "begin case " << i << " " << string(16, '=') << endl;
            input();
            ans_type ans = solve();
            if(debug_output) cout << string(16, '=') << endl;
            ans_type ans_simple = solve_simple();
            if(ans != ans_simple){
                cout << "input: " << endl;
                output_input();
                cout << "output: " << endl;
                output(ans);
                cout << "expected: " << endl;
                output(ans_simple);
            }
            if(debug_output) cout << "end case " << i << " " << string(16, '=') << endl;
        }
    }
    else{
        int64_t time_start = get_time();
        for(int i = 0; i < num_of_testcase; i++){
            input();
            output(solve());
        }
        int64_t time_end = get_time();

        if(calc_time){
            double time_per_case = (time_end - time_start) / (1e9 * num_of_testcase);
            cout << fixed << setprecision(3) << time_per_case << "[second/case]" << endl;
        }
    }

    return 0;
}