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 = list(input())
if S[0] != '<':
    S.insert(0,'<')
if S[-1] != '>':
    S.append('>')
con = []
count = 1
for i in range(len(S)-1):
    if S[i+1] == S[i]:
        count += 1
    else:
        con.append(count)
        count = 1
if S[-1] != S[-2]:
    count = 1
    con.append(count)
else:
    con.append(count)
ans = 0
for l in range(0,len(con)-1,2):
    if l % 2 == 0:
        f = con[l]
        b = con[l+1]
        if f >= b:
            ans += (1 + f)*f//2 + (b-1)*b//2
            
        else:
            ans += (1 + b)*b//2 + (f-1)*f//2
            
    else:
        pass
    
        
print(ans)