S = input()

C = []
run = 0
for c in S:
    if c == "<" or c == ">":
        C.append([c, 1])
    else:
        if len(C) > 0 and C[-1][0] == "=":
            C[-1][1] += 1
        else:
            C.append(["=", 1])

def found(stack):
    if len(stack) < 3:
        return False
    if stack[-3][0] == "<" and stack[-2][0] == "=" and stack[-1][0] == ">":
        return True
    return False

stack = []
for c, length in C:
    if c == "=" and len(stack) > 0 and stack[-1][0] == "=":
        stack[-1][1] += length
        continue
    stack.append([c, length])
    if found(stack):
        for _ in range(3):
            stack.pop()
ans = sum([length for _, length in stack])
print(ans)