#include <bits/stdc++.h>
using namespace std;

#ifdef _DEB
#define deb 1
#else
#define deb 0
#endif

using ll = long long;
#define rep(i, n) for(ll i = 0; i < n; ++i)
#define rep2(i, l, r) for(ll i = l; i < r; ++i)

using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;

#define all(A) A.begin(), A.end()
#define elif else if
using pii = pair<ll, ll>;

bool chmin(auto &a, auto b) {return a > b ? a = b, 1 : 0;}
bool chmax(auto &a, auto b) {return a < b ? a = b, 1 : 0;}

struct IOSetup {
  IOSetup() {
    cin.tie(0);
    ios::sync_with_stdio(0);
  }
} iosetup;

template<class T>
void print(vector<T> a) {
  for(auto x : a) cout << x << ' ';
  cout << endl;
}

void print(auto x) {cout << x << endl;}

template<class Head, class... Tail>
void print(Head &&head, Tail &&...tail) {
  cout << head << ' ';
  print(forward<Tail>(tail)...);
}

bool is_one(string S){
  int n=S.size();
  for(int i=0;i<n;i++){
    if(S[i]=='R'&&S[(i+1)%n]=='R')return 1;
  }
  return 0;
}

void solve_t1(vector<ll> L, vector<ll> R){
  ll n = L.size(), m = R.size();
  vector<ll> SL(n+1, 0), SR(m+1, 0);
  rep(i, n) SL[i+1] = SL[i] + L[i];
  rep(j, m) SR[j+1] = SR[j] + R[j];
  
  const ll INF = 1e15;
  vector<ll> dp(m+1, INF);
  dp[0] = 1;
  rep(i, n) {
    vector<ll> ndp(m+1, INF);
    rep(j, m+1) {
      ll d = dp[j];
      // to dp[i+1][j]
      {
        ll val = max({d, SL[i] - SR[j] + 1, SL[i+1] - SR[j] + 1});
        chmin(ndp[j], val);
      }
      // to dp[i+1][j+1]
      if(j < m) {
        ll val = INF;
        if(L[i] == R[j]) val = max(d, SL[i] - SR[j] + 2); // 階段型
        else val = max({d, SL[i] - SR[j] + 1, SL[i+1] - SR[j+1] + 1});
        chmin(ndp[j+1], val);
      }
    }
    swap(dp, ndp);
  }
  
  ll w = dp[m];
  assert(w > 0 && SR[m] + w - SL[n] > 0);
  ll yoko = n + m + w + (SR[m] + w - SL[n]);
  ll tate = 2 * (n+1);
  ll ans = tate + yoko;
  cout << ans << endl;
  return;
}

void solve_t2(string &S) {
  int n = S.size();
  vector<int> d(4,0);
  int r=0;
    
  for(int i=0;i<n;i++){
    if(S[i]=='L')r=(r+1)%4;
    else r=(r+3)%4;  
    d[r]++;
  }
  int an=(max(d[0],d[2])+max(d[1],d[3]))*2;
  if(d[0]==d[2]&&d[1]==d[3]){
      // an+=2;
      int y=0,x=0;
      int r=0;
      vector<int> dx={1,0,-1,0},dy={0,-1,0,1};
      set<pair<int,int>> SS;
      for(int i=0;i<n;i++){
          y+=dy[r];
          x+=dx[r];
          if(S[i]=='L')r=(r+1)%4;
          else r=(r+3)%4;
          if(SS.count({y,x})){
              an+=2;
              break;
          }
          SS.insert({y,x});
      }
  }
  cout<<an<<endl;
  return;
}

int main(){
  string S;
  cin>>S;
  int n=S.size();
  string H,W;
  if(is_one(S)){
    vector<int> d(4,0);
    int r=0;
    int an=0;
    for(int i=0;i<n;i++){
      if(S[i]=='L')r=(r+1)%4;
      else r=(r+3)%4;  
      (i%2==0?H:W).push_back("+-"[r/2]);
      d[r]++;
    }
    int HN=H.size();
    int WN=W.size();
    int cntH=0;
    for(int i=0;i<HN;i++){
      if(H[i]=='-'&&H[(i+1)%HN]=='+')cntH++;
    }
    if(cntH>1){
      rotate(S.begin(),S.begin()+1,S.end());
      r=0;
      H=W="";
      for(int i=0;i<n;i++){
        if(S[i]=='L')r=(r+1)%4;
        else r=(r+3)%4;  
        (i%2==0?H:W).push_back("+-"[r/2]);
        d[r]++;
      }
    }
    
    if(deb)cout<<H<<" "<<W<<endl;
    for(int i=0;i<HN;i++){
      if(H[i]=='-'&&H[(i+1)%HN]=='+'){
        rotate(H.begin(),H.begin()+i+1,H.end());
        rotate(W.begin(),W.begin()+i+1,W.end());
        break;
      }
    }
    if(deb)cout<<H<<" "<<W<<endl;
    string W1,W2;
    for(int i=0;i<HN;i++){
      if(H[i]=='+')W1.push_back(W[i]);
      else W2.push_back(W[i]);
    }
    if(deb)cout<<W1.back()<<" "<<W2.back()<<endl;
    W1.pop_back();
    W2.pop_back();
    reverse(all(W1));
    if(deb)cout<<W1<<" "<<W2<<endl;
    vector<ll> L, R;
    for(auto c : W2) L.emplace_back(c == '-' ? -1 : +1);
    for(auto c : W1) R.emplace_back(c == '-' ? +1 : -1);
    if(L.size() < R.size()) {
      swap(L, R);
      reverse(all(L));
      reverse(all(R));
    }
    if(deb) print(L), print(R);
    
    solve_t1(L, R);
  }
  else{
    solve_t2(S);
  }
  
  return 0;
}