import sys, math
sys.set_int_max_str_digits(0)
inf = 1<<60
MOD = 998244353

class Modint(int):
    mod = 998244353
    
    def modpow(self, i: int, r: int) -> int:
        return pow(i, r, Modint.mod)

    def modinv(self, i: int, r: int = 1) -> int:
        return pow(i, Modint.mod - 1 - r, Modint.mod)

    def __add__(self, other):
        return Modint(int.__add__(self, other) % Modint.mod)

    def __sub__(self, other):
        return Modint(int.__sub__(self, other) % Modint.mod)

    def __mul__(self, other):
        return Modint(int.__mul__(self, other) % Modint.mod)

    def __floordiv__(self, other):
        return Modint(int.__mul__(self, self.modinv(other)) % Modint.mod)

    __truediv__ = __floordiv__

    def __pow__(self, other):
        return Modint(self.modpow(self, other))

    def __radd__(self, other):
        return Modint(int.__add__(other, self) % Modint.mod)

    def __rsub__(self, other):
        return Modint(int.__sub__(other, self) % Modint.mod)

    def __rmul__(self, other):
        return Modint(int.__mul__(other, self) % Modint.mod)

    def __rfloordiv__(self, other):
        return Modint(int.__mul__(other, self.modinv(self)) % Modint.mod)

    __rtruediv__ = __rfloordiv__

    def __rpow__(self, other):
        return Modint(self.modpow(other, self))

    def __iadd__(self, other):
        self = self.__add__(other)
        return self

    def __isub__(self, other):
        self = self.__sub__(other)
        return self

    def __imul__(self, other):
        self = self.__mul__(other)
        return self

    def __ifloordiv__(self, other):
        self = self.__mul__(self.modinv(other))
        return self

    def __neg__(self):
        return (self.mod - self) % self.mod

    __itruediv__ = __ifloordiv__

    def __ipow__(self, other):
        self = Modint(self.modpow(self, other))
        return self

N = int(input())
S = ['U'] + list(input())
DP = [[Modint(0)] * (3) for _ in range(N + 1)]
# j == 0 : |
# j == 1 : \
# j == 2 : /
# 初期状態で | が一本たっているとする
DP[0][0] = 1
d = {}
d['U'] = 0
d['L'] = 1
d['R'] = 2

for i in range(N):
    if S[i] != '.':
        srcj = d[S[i]]
        # DP[i][srcj] からの寄与のみ考える
        if srcj <= 1:
            for j in range(3): #dst
                DP[i + 1][j] += DP[i][srcj]
        else:
            for j in [0, 2]:
                DP[i + 1][j] += DP[i][srcj]

    else: # '.' だったら全部
        for j in range(3):
            for dstj in range(3):
                # j == 2 and dstj == 1 のとき以外寄与つくる
                if j == 2 and dstj == 1:
                    continue
                DP[i + 1][dstj] += DP[i][j]

if S[-1] == '.':
    ans = sum(DP[-1])

else:
    ans = DP[-1][d[S[-1]]]

print(ans%MOD)