#include<bits/stdc++.h>
using namespace std;
int main(){
    long long n,p;
    string s;
    cin>>n>>p>>s;
    for(int i=0;i<n;i++){
        if(s[i]=='U'){
            if(p>1)p=p/2;
        }
        else if(s[i]=='L'){
            if(p<500000000000)p=p*2;
        }
        else if(p<499999999999)p=p*2+1;
    }
    cout<<p;
    return 0;
}