import java.util.*;
public class Main {
	public static void main(String... args) {
    	Scanner input = new Scanner(System.in);
        
        String str = input.next();
        
        int ans = 0;
        if (str.contains("RRR")) {
        	ans = 3;
        } else if (str.contains("RR")) {
        	ans = 2;
        } else if (str.contains("R")) {
        	ans = 1;
		}
        
        System.out.println(ans);
	}
}
/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