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: Runtime Error)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

public class AtCoderA
{
    static void Main()
    {
        var sc = new Scanner();

        string s = sc.Next();
        int[] nums = new int[s.Length + 1];

        if (s[0] == '<')
        {
            nums[0] = 0;
        }
        else
        {
            nums[0] = int.MaxValue;
        }

        if (s[s.Length - 1] == '<')
        {
            nums[s.Length] = int.MaxValue;
        }
        else
        {
            nums[s.Length] = 0;
        }

        for (int i = 0; i < s.Length - 1; i++)
        {
            if (s[i] == '>' && s[i + 1] == '<')
            {
                nums[i + 1] = 0;
            }
            else if (s[i] == '<' && s[i + 1] == '>')
            {
                nums[i + 1] = int.MaxValue;
            }
            else
            {
                nums[i + 1] = -1;
            }
        }

        for (int i = 1; i < s.Length; i++)
        {
            if (nums[i] != -1)
            {
                continue;
            }
            if (s[i - 1] == '<')
            {
                nums[i] = nums[i - 1] + 1;
            }
        }

        for (int i = s.Length - 1; i > 0; i--)
        {
            if (nums[i] != -1)
            {
                continue;
            }
            if (s[i] == '>')
            {
                nums[i] = nums[i + 1] + 1;
            }
        }

        for (int i = 1; i < s.Length; i++)
        {
            if (nums[i] != int.MaxValue)
            {
                continue;
            }
            nums[i] = Math.Max(nums[i - 1], nums[i + 1]) + 1;
        }

        if (nums[0] == int.MaxValue)
        {
            nums[0] = nums[1] + 1;
        }

        if (nums[s.Length] == int.MaxValue)
        {
            nums[s.Length] = nums[s.Length - 1] + 1;
        }

        long answer = nums.Sum();

        Console.WriteLine(answer);
    }

    class Scanner
    {
        private string[] _line;
        private int _index;
        private const char Separator = ' ';

        public Scanner()
        {
            _line = new string[0];
            _index = 0;
        }

        public string Next()
        {
            while (_index >= _line.Length)
            {
                _line = Console.ReadLine().Split(Separator);
                _index = 0;
            }

            return _line[_index++];
        }

        public int NextInt() => int.Parse(Next());
        public long NextLong() => long.Parse(Next());
        public double NextDouble() => double.Parse(Next());
        public decimal NextDecimal() => decimal.Parse(Next());
        public char NextChar() => Next()[0];
        public char[] NextCharArray() => Next().ToCharArray();

        public string[] Array()
        {
            _line = Console.ReadLine().Split(Separator);
            _index = _line.Length;
            return _line;
        }

        public int[] IntArray() => Array().Select(int.Parse).ToArray();
        public long[] LongArray() => Array().Select(long.Parse).ToArray();
        public double[] DoubleArray() => Array().Select(double.Parse).ToArray();
        public decimal[] DecimalArray() => Array().Select(decimal.Parse).ToArray();
    }
}