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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        String str = sc.next();
        int n = str.length();
        char c[] = str.toCharArray();
        
        long answer = 0;
        int count = 0;
        char now = '<';
        int left = 0;
        int right = 0;
        
        for (int i = 0; i < n; i++) {
            if (now == '<') {
                if (c[i] == '<') {
                    left++;
                } else {
                    now = '>';
                    right = 1;
                }
            } else {
                if (c[i] == '<') {
                    if (left > right) {
                        right--;
                    } else {
                        left--;
                    }
                    
                    while (left > 0) {
                        answer += left;
                        left--;
                    }
                    while (right > 0) {
                        answer += right;
                        right--;
                    }
                    now = '<';
                    left = 1;
                } else {
                    right++;
                }
            }
        }
        
        
        
        if (left > right) {
            right--;
        } else {
            left--;
        }
        
        while (left > 0) {
            answer += left;
            left--;
        }
        while (right > 0) {
            answer += right;
            right--;
        }
        
        System.out.println(answer);
    }
}