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

#define debug(x) cerr << #x << " = " << (x) << endl
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define mp make_pair
#define pb push_back
typedef long long ll;
typedef long double ld;
typedef pair<int, int> Pii;
typedef pair<ll, ll> Pll;

struct IOSetup
{
	IOSetup()
	{
		cin.tie(nullptr)->sync_with_stdio(false);
		cout << fixed << setprecision(16);
		cerr << fixed << setprecision(16);
	}
} iosetup;

template <typename T1, typename T2>
ostream &operator <<(ostream &os, const pair<T1, T2> &p)
{
	os << p.first << " " << p.second;
	return os;
}

template <typename T1, typename T2>
istream &operator >>(istream &is, pair<T1, T2> &p)
{
	is >> p.first >> p.second;
	return is;
}

template <typename T>
ostream &operator <<(ostream &os, const vector<T> &v)
{
	for(int i = 0; i < (int) v.size(); i++) os << v[i] << (i+1 == (int) v.size() ? "" : " ");
	return os;
}

template <typename T>
istream &operator >>(istream &is, vector<T> &v)
{
	for(int i = 0; i < (int) v.size(); i++) is >> v[i];
	return is;
}

template <typename T> bool chmax(T &a, const T &b) { if(a < b) { a = b; return true; } return false; }
template <typename T> bool chmin(T &a, const T &b) { if(a > b) { a = b; return true; } return false; }

////////////////////////////////////////////////////////

int main()
{
	string S; cin >> S;
	stack<Pii> st;
	for(char c : S)
	{
		if(c == '=')
		{
			if(!st.empty() && st.top().first == 1) st.top().second++;
			else st.push({1, 1});
		}
		else if(c == '<')
		{
			st.push({0, 1});
		}
		else
		{
			if(st.empty() || st.top().first != 1) st.push({2, 1});
			else
			{
				Pii tmp = st.top(); st.pop();
				if(!st.empty() && st.top().first == 0)
				{
					st.pop();
				}
				else st.push(tmp), st.push({2, 1});
			}
		}
	}
	int ans = 0;
	while(!st.empty())
	{
		ans += st.top().second; st.pop();
	}
	cout << ans << endl;
	return 0;
}