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: Wrong Answer)

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using System.Numerics;

namespace AtCoderWorkspace
{
    public class Solver
    {
        public void Solve()
        {
            var cin = new Scanner();
            var s = cin.next();

            var cc = s.ToCharArray();
            
            var daiCount = 1L;
            var syouCount = 0L;
            var ans = 0L;
            var before = cc[0];
            var daiLast = 0L;
            for (int i = 1; i < cc.Length; i++)
            {
                var now = cc[i];
               if(before == '<' && now == '<')
               {
                    syouCount++;
               }
               if(before == '<' && now == '>')
               {
                    daiLast = (syouCount+1);
                    ans += (syouCount * (syouCount + 1)) / 2;
                    syouCount = 0;                    
               }
               if(before == '>' && now == '>')
               {
                    daiCount++;
               }
               if(before == '>' && now == '<')
               {
                    if(daiLast > daiCount)
                    {
                        daiCount--;
                        ans += daiLast;
                        ans += (daiCount * (daiCount + 1)) / 2;
                    }
                    else
                    {
                        ans += (daiCount * (daiCount + 1)) / 2;
                    }
                    daiCount = 1;
               }
                before = now;
            }

            if(cc[cc.Length-1] == '<')
            {
                ans++;
            }
            else
            {
                if (daiLast > daiCount)
                {
                    daiCount--;
                    ans += daiLast;
                    ans += (daiCount * (daiCount + 1)) / 2;
                }
                else
                {
                    ans += (daiCount * (daiCount + 1)) / 2;
                }
            }

            Console.WriteLine(ans);
        }
    }

    class Scanner
    {
        string[] s;
        int i;

        char[] cs = new char[] { ' ' };

        public Scanner()
        {
            s = new string[0];
            i = 0;
        }

        public string next()
        {
            if (i < s.Length) return s[i++];
            string st = Console.ReadLine();
            while (st == "") st = Console.ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            if (s.Length == 0) return next();
            i = 0;
            return s[i++];
        }

        public int nextInt()
        {
            return int.Parse(next());
        }
        public int[] ArrayInt(int N, int add = 0)
        {
            int[] Array = new int[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextInt() + add;
            }
            return Array;
        }

        public int[] DPArrayInt(int N, int ex)
        {
            int[] Array = new int[N+ex];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextInt();
            }
            return Array;
        }

        public long nextLong()
        {
            return long.Parse(next());
        }

        public long[] ArrayLong(int N, long add = 0)
        {
            long[] Array = new long[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextLong() + add;
            }
            return Array;
        }

        public long[] DPArrayLong(int N, int ex)
        {
            long[] Array = new long[N + ex];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextLong();
            }
            return Array;
        }

        public double nextDouble()
        {
            return double.Parse(next());
        }


        public double[] ArrayDouble(int N, double add = 0)
        {
            double[] Array = new double[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextDouble() + add;
            }
            return Array;
        }
    }   

    class Program
    {
        static void Main(string[] s) => new Solver().Solve();
    }
}