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.Linq;
class c
{
    static void Main()
    {
        var s = Console.ReadLine();
        var x = new long[s.Length + 11];
        for (int i = 0; i < s.Length; i++)
        {
            if (s[i] == '<') x[i + 1] = x[i] + 1;
        }
        for (int i = s.Length-1; i >= 0; i--)
        {
            if (s[i] == '>')
            {
                x[i] = Math.Max(x[i + 1] + 1, x[i]);
            }
        }
        Console.WriteLine(x.Sum());
    }
}