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()+"1"
a=0
b=[]
i=0
l=len(s)
e=0
while True:
    if s[i]==s[i+1]:
        a+=1
    else:
        b.append(a+1)
        a=0
    i+=1
    if i+1>=l:
        break
if s[-2]=='<':
    b.append(0)
if s[0]=='>':
    b.insert(0,0)
for i in range(len(b)//2):
    c,d=max(b[i*2],b[i*2+1]),min(b[i*2],b[i*2+1])
    e+=(c*(c+1)//2)+(d*(d-1)//2)
print(e)