#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <string>
#include <utility>
#include <tuple>
#include <set>
#include <map>
#include <cassert>

using namespace std;

int main() {
	string s;
	cin >> s;

	char pre = '?';
	string t;
	for (char c: s) {
		if (c != '=') {
			t += c;
		} else {
			if (pre != '=') {
				t += c;
			}
		}
		pre = c;
	}

	string u;
	for (char c: t) {
		u += c;
		if (u.size() < 3) { continue; }

		if (u.ends_with("<=>")) {
			u.pop_back();
			u.pop_back();
			u.pop_back();
		}
	}

	cout << u.size() << endl;

	return 0;
}