#include <iostream>
#include <vector>

using namespace std;
using ll = long long;


int main(){
  string s;
  cin >> s;
  vector<pair<int, int>> stack;
  for (char i: s){
    if (i == '<') {
      stack.emplace_back(0, 1);
    }
    else if (i == '='){
      if (stack.empty() || stack.back().first != 1)
        stack.emplace_back(1, 1);
      else stack.back().second++;
    }
    else{
      if (stack.size() >= 2 && stack[stack.size() - 2].first == 0 && stack.back().first == 1){
        stack.pop_back();
        stack.pop_back();
      }
      else stack.emplace_back(2, 1);
    }
  }
  int ans = 0;
  for(auto p: stack) ans += p.second;
  cout << ans << endl;
}