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 Python (3.4.3) (judge verdict: Accepted)

s=input()
n=len(s)+1
ans=[0]
p=s[::-1]
cnt=0
for i in range(n-1):
	if s[-i-1]==">":
		cnt+=1
	else:
		cnt=0
	ans.append(cnt)
ansk=[]
for i in range(n):
	ansk.append(ans[-i-1])
import copy
kari=copy.copy(ansk)
cnt=0
for i in range(n-1):
	if kari[i]==kari[i+1]==0:
		cnt+=1
		ansk[i+1]=cnt
	else:
		if kari[i]==0:
			if ansk[i+1]<=ansk[i]:
				ansk[i+1]=ansk[i]+1
		cnt=0
print(sum(ansk))