Problem:
Score : 300 points

Problem Statement

Given is a string S of length N-1.
Each character in S is < or >.

A sequence of N non-negative integers, a_1,a_2,\cdots,a_N, is said to be good when the following condition is satisfied for all i (1 \leq i \leq N-1):

If S_i= <: a_i<a_{i+1}

If S_i= >: a_i>a_{i+1}

Find the minimum possible sum of the elements of a good sequence of N non-negative integers.

Constraints

2 \leq N \leq 5 \times 10^5

S is a string of length N-1 consisting of < and >.

Input

Input is given from Standard Input in the following format:

S

Output

Find the minimum possible sum of the elements of a good sequence of N non-negative integers.

Sample Input 1

<>>

Sample Output 1

3

a=(0,2,1,0) is a good sequence whose sum is 3.
There is no good sequence whose sum is less than 3.

Sample Input 2

<>>><<><<<<<>>><

Sample Output 2

28

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
class Program
    {
        static void Main(string[] args)
    	{
            string s = Console.ReadLine();
            int n = 0;
            int last_n = 0;
            long ans = 0;
            bool up = true;

            if(s[0] == '>')
            {
                //up = false;
                ans = 1;
            }

            for (int i=0; i<s.Length; i++)
            {
                if(s[i] == '<')
                {
                    if (up)
                    {
                        n++;
                        ans += n;
                    }
                    else
                    {
                        n = 1;
                        ans += 1;
                        up = true;
                    }
                }
                else
                {
                    if (up)
                    {
                        last_n = n;
                        n = 0;
                        up = false;
                    }
                    else
                    {
                        n++;
                        if (last_n > n)
                        {
                            ans += n;
                        }
                        else
                        {
                            ans += n + 1;
                        }
                    }
                }
            }

            Console.WriteLine(ans);
            
        }
    
    }
    //mcs Main.cs
    //mono Main.exe