#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
int n;
char cmd[1000001];
bool sym(int p) {
  int rm = 0, cur = 0;
  for (int i = 0; i < n - 1; ++i) {
    if (cur > p + 1 && cmd[i] == 'L')
      cur--;
    else if (cmd[i] == 'R')
      rm = max(rm, ++cur);
  }
  return cur + 1 > rm;
}
int main() {
  scanf("%s", cmd);
  n = strlen(cmd);
  if (cmd[n - 1] == 'L')
    for (int i = 0; i < n; ++i) cmd[i] = cmd[i] == 'R' ? 'L' : 'R';
  if (sym(-mod))
    puts("1");
  else {
    int a = -mod, b = 0;
    while (b - a > 1) {
      int m = (a + b) >> 1;
      if (sym(m))
        b = m;
      else
        a = m;
    }
    printf("%d\n", -b);
  }
  return 0;
}
