from collections import deque, defaultdict, Counter
from bisect import bisect_left, bisect_right
from itertools import permutations, combinations
from functools import cmp_to_key, cache
from heapq import heappop, heappush
import math, sys
import pypyjit
pypyjit.set_param('max_unroll_recursion=-1')
sys.setrecursionlimit(10**7)
_int = lambda x: int(x)-1
MOD = 998244353
INF = 1<<62
Yes, No = "Yes", "No"

S = input()
N = len(S)
minus = 0
stack = []
C = defaultdict(int)
for i, c in enumerate(S):
    if c == "<":
        stack.append(i)
    elif c == ">":
        if stack:
            l = stack.pop()
            if C[l] > 0:
                minus += C[l]+2
            else:
                stack.append(l)
                C[l] = -1
    else:
        if stack:
            l = stack[-1]
            if C[l] >= 0:
                C[l] += 1
print(N-minus)