using System.Collections.Generic;
using System;

public class Hello
{
    static void Main()
    {
        var s = Console.ReadLine().Trim();
        getAns(s);
    }
    static void getAns(string s)
    {
        var st = new Stack<int>();
        var f = false;
        foreach (var x in s)
        {
            if (x == '<') { st.Push(0); f = false; }
            else if (x == '=')
            {
                var top = st.Peek();
                if (top == 0) f = true;
                else if (top == 1) continue;
                st.Push(1);
            }
            else
            {
                if (f)
                {
                    while (true)
                    {
                        if (st.Pop() == 0) break;
                    }
                }
                else st.Push(2);
            }
        }
        Console.WriteLine(st.Count);
    }
}