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 = s.Length;
		int[]A = new int[s.Length+1];
		int[]B = new int[s.Length+1];
		int c = 0;
		for(var i=0;i<N;i++){
			if(s.Substring(i,1)=="<"){
				c++;
			} else {
				c = 0;
			}
			A[i+1] = c;
		}
		c = 0;
		for(var i=N-1;i>=0;i--){
			if(s.Substring(i,1)==">"){
				c++;
			} else {
				c = 0;
			}
			B[i] = c;
		}
		long ans = 0;
		for(var i=0;i<N+1;i++){
			ans += Math.Max(A[i],B[i]);
		}
		Console.WriteLine(ans);
	}
}