#include <bits/stdc++.h>
using namespace std;
char s[1000011];
int n;
bool OK(int m) {
  int i, mr = -1000011, ml = 1000011, S = 0;
  for (int i = 0; i < n; i++) {
    if (s[i] == 'R' && S < m - 1) {
      S++;
    } else if (s[i] == 'L')
      S--;
    if (i != n - 1) {
      mr = max(mr, S);
      ml = min(ml, S);
    }
  }
  if (S < 0 && S < ml) return true;
  return false;
}
int main() {
  int i, j, R = 0, L = 0, S = 0, mr = -1000011, ml = 1000011;
  scanf("%s", s);
  n = strlen(s);
  for (i = 0; i < n; i++) {
    if (s[i] == 'R')
      S++;
    else
      S--;
    if (i != n - 1) {
      mr = max(mr, S);
      ml = min(ml, S);
    }
  }
  if (S != 0 && (S > mr || S < ml)) {
    printf("1\n");
    return 0;
  }
  mr = max(mr, S);
  ml = min(ml, S);
  if (s[n - 1] == 'R')
    for (i = 0; i < n; i++) {
      if (s[i] == 'R') {
        s[i] = 'L';
        S--;
        L++;
      } else {
        s[i] = 'R';
        S++;
        R++;
      }
      if (i != n - 1) {
        mr = max(mr, S);
        ml = min(ml, S);
      }
    }
  if (S < 0 && S < ml) {
    printf("1\n");
    return 0;
  }
  int l = 1, r = mr, m = 0;
  while (l <= r) {
    m = (l + r) / 2;
    if (OK(m) == false) {
      r = m - 1;
    } else {
      l = m + 1;
    }
  }
  if (r < 0) r = 0;
  printf("%d\n", r);
  return 0;
}
