from sys import stdin

mod = 998244353


def main():
    n = int(stdin.readline())
    s = stdin.readline().rstrip()
    dpL = [0] * n
    dpR = [0] * n
    dpU = [0] * n

    if s[0] == 'L':
        dpL[0] = 1
    elif s[0] == 'R':
        dpR[0] = 1
    elif s[0] == 'U':
        dpU[0] = 1
    else:
        dpL[0] = dpR[0] = dpU[0] = 1

    for i in range(1, n):
        if s[i] == 'L':
            dpL[i] += dpL[i-1]
            dpL[i] += dpU[i-1]
        elif s[i] == 'R':
            dpR[i] += dpL[i-1]
            dpR[i] += dpR[i-1]
            dpR[i] += dpU[i-1]
        elif s[i] == 'U':
            dpU[i] += dpL[i-1]
            dpU[i] += dpR[i-1]
            dpU[i] += dpU[i-1]
        else:
            dpL[i] += dpL[i-1]
            dpL[i] += dpU[i-1]
            dpR[i] += dpL[i-1]
            dpR[i] += dpR[i-1]
            dpR[i] += dpU[i-1]
            dpU[i] += dpL[i-1]
            dpU[i] += dpR[i-1]
            dpU[i] += dpU[i-1]

        dpL[i] %= mod
        dpR[i] %= mod
        dpU[i] %= mod

    # print(dpL)
    # print(dpR)
    print((dpL[-1] + dpR[-1] + dpU[-1]) % mod)
    return


if __name__ == "__main__":
    main()