#include <bits/stdc++.h>
using namespace std;

void fast_io() {
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
}

int main() {
	fast_io();
	string s;
	cin >> s;
	string st = "";
	bool has_l = false, has_e = false;
	for (char c : s) {
		if (c == '<') {
			has_l = true;
			has_e = false;
			st += c;
		} else if (c == '=') {
			if (has_l) {
				has_e = true;
			}
			st += c;
		} else {
			if (has_l && has_e) {
				while (st.back() == '=') {
					st.pop_back();
				}
				assert(st.back() == '<');
				st.pop_back();
			} else {
				has_l = false;
				has_e = false;
				st += c;
			}
		}
	}
	cout << st.size() << endl;
}