#include <iostream>
#include <vector>
#include <string>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    string s;
    cin >> s;
    int n = s.size();

    vector<int> v(n);
    int now = 0;
    vector<bool> co(n, true);
    vector<bool> judge(n, true);
    vector<char> st;

    rep(i, n){
        st.push_back(s[i]);

        if(s[i] == '<'){
            now++;
            if (now >= n) now = n - 1;
        }
        else if(s[i] == '>'){
            if(now > 0 && judge[now]){
                if(v[now] == 0){
                    v[now] = 0;
                    now--;
                    if(now >= 0) judge[now] = false;
                    if(now == 0) judge = co;
                }
                else{
                    int cnt = v[now] + 2;
                    if(st.size() >= cnt){ 
                        for(int j = 0; j < cnt; j++){
                            st.pop_back();
                        }
                    }
                    v[now] = 0;
                    now--;
                }
            }
        }
        else {
            if(now >= 0 && now < n) {
                v[now]++;
            }
        }
        if (now < 0) now = 0;
    }

    cout << st.size() << endl;
}