//                                                     /*[*/#include<stdio.h>//
//                         #include<stdlib.h>//]++++[->++[->+>++++<<]<][(c)2013]
//                        #ifndef                                           e//[o
//                       #include<string.h>//]![misaka.c,size=3808,crc=d0ec3b36][
//                      #define e                                           0x1//
//                     typedef struct{ll  d,b,o,P;char*q,*p;}f;ll  p,q,d,b,_=0//|
//                  #include __FILE__//]>>[->+>++<<]<[-<<+>>++<]>>+MISAKA*IMOUTO
//                #undef e//[->[-<<+<+<+>>]<<<<<++[->>+>>+<<<<<]>+>+++>+++[>]]b
//             #define e(c)/**/if((_!=__LINE__?(_=__LINE__):0)){c;}//[20002,+[-.+]
//            ,O,i=0,Q=sizeof(f);static f*P;static FILE*t;static const char*o[]={//
//          "\n\40\"8oCan\40not\40open %s\n\0aaFbfeccdeaEbgecbbcda6bcedd#e(bbed$bbd",
//        "a6bgcdbbccd#ead$c%bcdea7bccde*b$eebbdda9bsdbeccdbbecdcbbcceed#eaa&bae$cbe",
//       "e&cbdd$eldbdeedbbdede)bdcdea&bbde1bedbbcc&b#ccdee&bdcdea'bbcd)e'bad(bae&bccd",
//      "e&bbda1bdcdee$bbce#b$c&bdedcd%ecdca4bhcdeebbcd#e$b#ecdcc$bccda7bbcc#e#d%c*bbda",
//     ">bad/bbda"};static ll  S(){return(o[p][q]);}static/**/ll /**/Z=0  ;void/**/z(ll //
//    l){if(/**/Z-l){Z=l;q++;if(p<b*5&&!S()){p+=b;q=0;}}}ll  main(ll  I,    /**/char**l){//
//   d=sizeof(f*);if(1<(O=_)){b=((sizeof(o)/sizeof(char*))-1)/4;q=22; p=     0;while(p<b*5){
//  /*<*/if(Z-1){d=S()>96;i=S()-(d?96:32) ;q++;if(p<b*5&&!S()){p+=b;  q=      0;}Z=1;}/*[[*/
//  while(i){_=o[0][S()-97];I=_-10?b:1;   for( ;I--;)putchar(_ );if   (!      --i||d)z(~i );}
// if(p==b*5&&O){p-=b;O--;}}return 0U;   }if(! (P=( f*)calloc /*]*/  (Q        ,I)))return 1;
// {;}for(_=p=1;p<I;p++){e(q=1);while    (q<   p&&  strcmp(  l[p     ]         ,l[(q)]))++  q;
// t=stdin;if(q<p){(void)memcpy/* "      */    (&P  [p],&P   [q     ]          ,Q);continue ;}
//if(strcmp(l[p],"-")){t=fopen(l         [     p]   ,"rb"   )                  ;if(!t ){{;}  ;
//prll f(05+*o,l[p ]);return+1;                      {;}                       }}_=b= 1<<16   ;
//*&O=5;do{if(!(P[p].q=realloc   (P[p].q,(P[p].P     +=       b)+1))){return   01;}O   &=72   /
//6/*][*/;P[p].o+=d=fread(P[p]      .q       +P[     p           ].       o,  1,b,t)   ;}//
// while(d==b)      ;P [p].q[       P[       p]                  .o       ]=  012;d    =0;
// e(fclose(t        )  );P         [p]      .p                  =P[      p]  .q;if    (O)
// {for(;d<P[            p]          .o     ;d=                   q+     1)    {q=     d;
//  while(q<P[                        p].o&&P[                    p].q[q]-     10     ){
//  q++;}b=q-d;                         _=P                         [p].        d     ;
//  if(b>_){/*]b                                                                */
//   P[p].d=b;}{;                                                                }
//   #undef/*pqdz'.*/  e//                                                      ;       
//   #define/*s8qdb]*/e/**/0                                                   //
//   //<<.<<.----.>.<<.>++.++<                                              .[>]
//   /*P[*/P[p].b++;continue;}}}t=                                       stdout;
//  for (p=1;p<I;p++){/**/if(P[p].b>i                               ){i=P[p].b;}}
// if  (O){for(p=0;p<i;p++){q=0;/*[*/while(I               >++q){_=P[q].p-P[q ].q;
//b=   0;if(_<P[q ].o){while(012-*P[q].p)     {putchar(*(P[q].p++));b++;}P[q]. p++;
//}   ;while (P[  q].d>b++)putchar(040);}             putchar(10);}return 0;}p   =1;
//   for(;   p<I   ;p++)fwrite(P[p] .q,P[              p].o,1,t);return 0 ;}//
//  #/*]     ]<.    [-]<[-]<[- ]<[    -]<               [-  ]<;*/elif  e    //b
// |(1        <<     ( __LINE__        /*               >>   `*//45))  |     01U   //by pravesh  vajpayee ;-)
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
using namespace __gnu_pbds; 
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
using namespace std;
#define ll long long int
#define ld long double
#define ff first
#define ss second  
#define endl '\n'
#define pb push_back
#define t_case ll tt; cin>>tt; while (tt--)
#define all(v) v.begin(),v.end()
#define ub(a,x) upper_bound(all(a),x)-a.begin()
#define lb(a,x) lower_bound(all(a),x)-a.begin()
#define fr(a,b,c) for (ll a=b;a<c;a++)
#define take(xx,n) for (int i=0;i<n;i++) cin>>xx[i];
#define take1(xx,n) for (int i=1;i<=n;i++) cin>>xx[i];
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL);
 
int main() 
{
	fastio
	//t_case
	{
		ll sum=0,f=0,ans=0,n,m=0,k=0,z=0,mx=0,mn=LLONG_MAX,q  ;
		string s; cin>>s;
		for (auto i:s){
          	if (i=='R') m++;
          	else m=0;
          	ans=max(m,ans);
        }
		cout<<ans;
		cout<<endl;
	}
	return 0;
}

Measured memory_bytes: 3648