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 (1.6) (judge verdict: Accepted)

package main

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

func solution(s string) int {
        n := len(s) + 1
        a := make([]int, n)
        for i := 0; i < n-1; i++ {
                if s[i] == '<' {
                        a[i+1] = max(a[i+1], a[i]+1)
                }
        }

        for i := n - 2; i >= 0; i-- {
                if s[i] == '>' {
                        a[i] = max(a[i], a[i+1]+1)
                }
        }
        out := 0
        for i := 0; i < n; i++ {
                out += a[i]
        }
        return out
}

func max(x, y int) int {
        if x > y {
                return x
        }
        return y
}

func main() {
        var fp *os.File = os.Stdin
        reader := bufio.NewReaderSize(fp, 1024)
        s := readLine(reader)
        fmt.Println(solution(s))
}

func readLine(reader *bufio.Reader) string {
        buf := make([]byte, 0, 1024)

        for {
                l, p, _ := reader.ReadLine()

                buf = append(buf, l...)

                if !p {
                        break
                }
        }
        return string(buf)
}