#include <bits/stdc++.h>
using namespace std;
const double pi = acos(-1.0);
const double eps = 1e-11;
template <class T>
inline void Min(T &a, T b) {
  if (b < a) a = b;
}
template <class T>
inline void Max(T &a, T b) {
  if (b > a) a = b;
}
template <class T>
inline T gcd(T a, T b) {
  if (a < 0) return gcd(-a, b);
  if (b < 0) return gcd(a, -b);
  return (b == 0) ? a : gcd(b, a % b);
}
template <class T>
inline T lcm(T a, T b) {
  if (a < 0) return lcm(-a, b);
  if (b < 0) return lcm(a, -b);
  return a * (b / gcd(a, b));
}
template <class T>
inline T euclide(T a, T b, T &x, T &y) {
  if (a < 0) {
    T d = euclide(-a, b, x, y);
    x = -x;
    return d;
  }
  if (b < 0) {
    T d = euclide(a, -b, x, y);
    y = -y;
    return d;
  }
  if (b == 0) {
    x = 1;
    y = 0;
    return a;
  } else {
    T d = euclide(b, a % b, x, y);
    T t = x;
    x = y;
    y = t - (a / b) * y;
    return d;
  }
}
char s[1000002];
int n, mx, mn, now, ans;
bool check(int pos) {
  mx = mn = now = 0;
  for (int i = 1; i <= n; i++) {
    if (s[i] == 'L') {
      now -= 1;
      if (i != n) mn = min(mn, now);
    } else {
      now += 1;
      if (now == pos) now--;
      if (i != n) mx = max(mx, now);
    }
  }
  if (now > mx || now < mn) return true;
  return false;
}
int solve() {
  int l = 1, r = n, res = 0;
  while (l < r) {
    int mid = (l + r) / 2;
    if (check(mid)) {
      l = mid + 1;
      res = mid;
    } else
      r = mid;
  }
  return res;
}
int main() {
  cin >> s + 1;
  n = strlen(s + 1);
  mx = mn = now = 0;
  for (int i = 1; i <= n; i++) {
    if (s[i] == 'L') {
      now -= 1;
      if (i != n) mn = min(mn, now);
    } else {
      now += 1;
      if (i != n) mx = max(mx, now);
    }
  }
  if (now > mx || now < mn) {
    cout << 1 << endl;
    return 0;
  }
  ans = solve();
  for (int i = 1; i <= n; i++)
    if (s[i] == 'L')
      s[i] = 'R';
    else
      s[i] = 'L';
  ans += solve();
  cout << ans << endl;
  return 0;
}
