#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1000005;
char s[MAXN];
int hehe[MAXN];
int n;
int check(int pos) {
  int s = 0;
  int mx = 0;
  int ok = 0;
  for (int i = 1; i <= n; i++) {
    if (hehe[i]) {
      s--;
      if (i == n && s < mx) {
        return ok;
      }
      mx = min(mx, s);
    } else if (s + 1 < pos)
      s++;
    else if (s + 1 >= pos)
      ok = 1;
  }
  return 0;
}
int main() {
  scanf("%s", s);
  n = strlen(s);
  for (int i = 1; i <= n; i++) {
    int v = s[i - 1] == s[n - 1] ? 1 : 0;
    hehe[i] = v;
  }
  int ss = 0;
  int l = 0;
  int r = 0;
  for (int i = 1; i <= n; i++) {
    if (hehe[i]) {
      ss--;
      if (i == n && ss < l) {
        printf("1\n");
        return 0;
      }
      l = min(l, ss);
    } else {
      ss++;
      if (i == n && ss > r) {
        printf("1\n");
        return 0;
      }
      r = max(r, ss);
    }
  }
  int ans = 0;
  int ll = 1, rr = 1000000;
  while (ll <= rr) {
    int m = ll + rr >> 1;
    if (check(m)) {
      ans = m;
      ll = m + 1;
    } else
      rr = m - 1;
  }
  printf("%d\n", ans);
  return 0;
}
