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 Kotlin (1.3.71) (judge verdict: Accepted)

import kotlin.math.max
import kotlin.math.min

fun main(args: Array<String>) {
    val regex = Regex("<*>*")
    val s = regex.findAll(readString()).map { it.value }.toList()

    var ans = 0L
    s.forEach {
        val gt = it.count { it == '<' }
        val lt = it.count { it == '>' }

        for (i in 0..max(gt, lt)) {
            ans += i
        }
        for (i in 0 until min(gt, lt)) {
            ans += i
        }
    }
    println(ans)
}

// Tools
fun readString() = readLine()!!