题解在此

#include <iostream>
using namespace std;
int main(){
    int n;
    cin>>n;
    long long ans=0;
    for (int i=1;i<=2*n;i++){
        ans*=4;
        char c;
        cin>>c;
        switch (c){
            case 'L':ans+=2;break;
            case 'R':ans+=0;break;
            case 'U':ans+=3;break;
            case 'D':ans+=1;break;
        }
    }
    cout<<ans;
    return 0;
}