import java.io.*;

class Process {
    private String S;
    
    Process(String S) {
        this.S = S;
    }

    int getResult() {
        int roadNum = 1;
        
        for(int i = 0; i < S.length(); i++) {
            roadNum *= 2;
            
            if(S.charAt(i) == 'R') {
                roadNum++;
            }
        }

        return roadNum;
    }
}

public class Main {
    public static void main(String[] args) throws IOException {
        var bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        var printWriter    = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));

        // 入力
        String S = bufferedReader.readLine().trim();
        
        // 処理および出力
        printWriter.println((new Process(S)).getResult());

        bufferedReader.close();
        printWriter.close();
    }
}