    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;

    public class Main {

        public static void main(String[] args) throws IOException {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            String line = br.readLine();

            if(line.contains("RRR")){
                System.out.println("3");
            }
            else if(line.contains("RR")){
                System.out.println("2");
            }
            else if(line.contains("R")){
                System.out.println(1);
            }
            else {
                System.out.println(0);
            }
        }
    }
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz