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 Go (1.14.1) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	S := ReadString()
	v := make([]int, len(S)+1)

	for i := 0; i < len(S); i++ {
		if S[i] == '<' {
			v[i+1] = v[i] + 1
		}
	}
	for i := len(S) - 1; i >= 0; i-- {
		if S[i] == '>' {
			v[i] = Max(v[i], v[i+1]+1)
		}
	}

	ans := 0
	for _, a := range v {
		ans += a
	}
	fmt.Println(ans)
}

func Max(xs ...int) int {
	max := xs[0]
	for _, x := range xs[1:] {
		if max < x {
			max = x
		}
	}
	return max
}

var reader = bufio.NewReader(os.Stdin)

func Scan(a ...interface{}) {
	if _, err := fmt.Fscan(reader, a...); err != nil {
		panic(err)
	}
}
func ReadString() (s string) { Scan(&s); return }