#include <bits/stdc++.h>
using namespace std;
#define int long long
int n, s, ans;
char opt;

signed main() {
    cin >> n >> s;
    for (int i = 1; i <= n; i++) {
        cin >> opt;
        if (opt == 'U') {
            if (s != 1) s /= 2;
        } else if (s == 'L') {
            s *= 2;
        } else if (opt == 'R') {
            s = s * 2 + 1;
        }
    }
    cout << s;
    return 0;
}

为何错误，本人考 7 级，题目只看了一会会。