题解

#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
    string s;
    int n,m;
    cin>>n>>m;
    cin>>s;
    stack<char>t;
    for(int i=0;i<n;i++){
        if(s[i]=='U'){
            if(!t.empty()){
                t.pop();
            }
            else{
                if(m!=1){
                   m=m/2; 
                }
            }
        }
        if(s[i]=='L'||s[i]=='R'){
            t.push(s[i]);
        }
    }
    stack<char>s1;
    while(!t.empty()){
        s1.push(t.top());
        t.pop();
    }
    while(!s1.empty()){
        if(s1.top()=='R'){
            m=m*2+1;
        }
        else{
            m=m*2;
        }
        s1.pop();
    }
    cout<<m;
    return 0;
}