#include<bits/stdc++.h>
using namespace std;
#define int long long
signed main() {
	string s;
	cin >> s;
	int n = s.size();
	deque<pair<int,char>> q;
	for(int i = 0; i < n; i++) {
		if(s[i] != '>') {
			int l = q.size();
			if(l == 0) q.push_back({1,s[i]});
			else if(q.back().second == s[i]) q.back().first++;
			else q.push_back({1,s[i]});
		}
		else {
			int l = q.size();
			if(l == 0) q.push_back({1,s[i]});
			else if(l == 1) {
				if(q.back().second == s[i]) q.back().first++;
				else q.push_back({1,s[i]});
			}
			else {
				if(q.back().second != '=') {
					if(q.back().second == s[i]) q.back().first++;
			    	else q.push_back({1,s[i]});
				}
				else {
					int x = q.back().first;
					q.pop_back();
					if(q.back().second != '<') {
						q.push_back({x,'='});
						if(q.back().second == s[i]) q.back().first++;
			         	else q.push_back({1,s[i]});
					}
					else {
						q.back().first--;
						if(q.back().first == 0) q.pop_back();
					}
				}
			}
		}
	}
	int ans = 0;
	while(q.size() > 0) {
		ans+=q.front().first;
		q.pop_front();
	}
	cout << ans << endl;
}