#import<stdio.h>
#define Z(S,N)puts(S),fflush(stdout),scanf("%d",&N);
N;main(x){
	for(gets(&N);;){
		Z("L",N)
		for(x=99;--x;){
			Z("R",N)
			for(;!N;){
				Z("L",N)
			}
			if(N>50){
				for(x=50;--x;)puts("F");
				exit(0);
			}
			Z("F",N)
		}
		for(;N--;){
			Z("F",x)
		}
	}
}