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;

namespace agc040a
{
    class Program
    {
        static void Main(string[] args)
        {
            var S = Console.ReadLine();
            int sum = 0;
            int left_num = 0;
            int right_num = 0;
            for(int i = 0; i <= S.Length; i++){
                int down_count = i-1;
                int up_count = i;
                right_num = 0;
                left_num = 0;
                while( 0 < down_count){
                    if(S[down_count]=='<'){
                        left_num++;
                    }else{
                        break;
                    }
                    down_count--;
                }
                while(up_count < S.Length){
                    if(S[up_count]=='>'){
                        right_num++;
                    }else{
                        break;
                    }
                    up_count++;
                }
                sum += Math.Max(left_num,right_num);
            }
            Console.WriteLine(sum);
        }
    }
}