s = input()
que = []
for c in s:
    if c == "<":
        que.append((1, c))
    elif c == "=":
        if len(que) > 0:
            bef = que.pop()
            if bef[1] == "=":
                que.append((bef[0] + 1, c))
            else:
                que.append(bef)
                que.append((1, c))
        else:
            que.append((1, c))
    elif c == ">":
        if len(que) >= 2:
            bef = que.pop()
            befbef = que.pop()
            if bef[1] == "=" and befbef[1] == "<":
                continue
            else:
                que.append(befbef)
                que.append(bef)
                que.append((1, c))
        else:
            que.append((1, c))

ans = 0
while que:
    cnt, _ = que.pop()
    ans += cnt
print(ans)