#include <iostream>
#include <cmath>
#include <stack>
#include <iomanip>
#include <limits>
#include <queue>
#include <map>
#include <set>
#include<algorithm>
#include<deque>
using namespace std;
#define rep(i, n) for (int i = 0;i < (n); ++i)
#define Yes cout << "Yes" << endl
#define No cout << "No" << endl
#define vi vector<int>
#define vvi vector<vector<int>>
#define vl vector<long long> 
#define vvl vector<vector<long long>>
#define vs vector<string>
#define vc vector<char>
#define vvc vector<vector<char>>
#define vb vector<bool>
#define vvb vector<vector<bool>> 
using ll = long long;
using P = pair<ll,ll>;
void chmin(ll &a,ll b){
    a = min(a,b);
}
void chmax(int &a,int b){
    a = max(a,b);
} 

const ll INF = 2e18;

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++;
        }
        else if(s[i] == '>'){
            if(!judge[now])continue;
            if(v[now] == 0){
                v[now] = 0;
                now--;
                if(now != 0)judge[now] = false;
                if(now == 0)judge = co;
            }
            else{
                if(now == 0)continue;
                int cnt = v[now]+2;
                for(int i = 0;i < cnt;i++){
                    st.pop_back();
                }
                v[now] = 0;
                now--;
            }
        }
        else{
            v[now]++;
        }
    }
    cout << st.size() << endl;
}