#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  string s;
  cin >> s;
  stack<pair<char, int>> st;
  for (char c : s) {
    bool flag = false;
    if (st.size() >= 2) {
      auto [c1, cnt1] = st.top();
      st.pop();
      auto [c2, cnt2] = st.top();
      st.pop();
      if (c2 == '<' && c1 == '=' && c == '>') {
        flag = true;
      }
      else {
        st.push({ c2, cnt2 });
        st.push({ c1, cnt1 });
      }
    }
    if (!flag) {
      if (c == '=' && !st.empty() && st.top().first == '=') {
        st.top().second++;
      }
      else {
        st.push({ c, 1 });
      }
    }
    Debug(st);
  }
  int ans = 0;
  while (!st.empty()) {
    auto [c, cnt] = st.top();
    st.pop();
    ans += cnt;
  }
  cout << ans << endl;
  return 0;
}