# oj t -c "python3 main.py"
import sys,math
from collections import defaultdict,deque
from itertools import combinations,permutations,accumulate,product
from bisect import bisect_left,bisect_right
from heapq import heappop,heappush,heapify
#from more_itertools import distinct_permutations,distinct_combinations
#from sortedcontainers import SortedList,SortedSet
def input():return sys.stdin.readline().rstrip()
def ii(): return int(input())
def ms(): return map(int, input().split())
def li(): return list(map(int,input().split()))
inf = pow(10,18)
mod = 998244353
#/////////////////////////////////
S = input()
que = deque()
cnt = 0
for s in S:
    #print(que,s,len(que))
    if s=="<":
        cnt += 1
        que.append(s)
    elif s==">":
        if cnt==0 or que[-1]=="<":
            que.append(s)
        else:
            remove = deque()
            while que:
                n = que.pop()
                remove.append(n)
                if n=="<": 
                    cnt -= 1
                    break
                if n==">":
                    while remove:
                        n = remove.pop()
                        que.append(n)
                    que.append(s)
                    break
    else:
        que.append(s)
print(len(que))