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

#ifdef LOCAL
#include <debug_print.hpp>
#define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (static_cast<void>(0))
#endif

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
    string S;
    cin >> S;

    int N = S.size(), ans = N;
    stack<pair<char, int>> stk;
    for (int i = 0; i < N; i++) {
        if (stk.empty()) {
            stk.emplace(S[i], 1);
        } else {
            if (S[i] == '=' && stk.top().first == '=') {
                stk.top().second++;
            } else {
                stk.emplace(S[i], 1);
            }
        }
        while (stk.size() >= 3) {
            auto [c3, cnt3] = stk.top();
            stk.pop();
            auto [c2, cnt2] = stk.top();
            stk.pop();
            auto [c1, cnt1] = stk.top();
            stk.pop();
            if (c1 == '<' && c2 == '=' && c3 == '>') {
                ans -= cnt2 + 2;
            } else {
                stk.emplace(c1, cnt1);
                stk.emplace(c2, cnt2);
                stk.emplace(c3, cnt3);
                break;
            }
        }
    }

    cout << ans << '\n';
}