S = input()
cur = []
for c in S:
    if c == '=':
        if len(cur) and cur[-1][0]=='=':
            cur[-1][1]+=1
        else:
            cur.append([c, 1])
    else:
        cur.append([c, 1])
        if len(cur)>=3 and cur[-3][0] == '<' and cur[-2][0] == '=' and cur[-1][0] == '>':
            cur.pop()
            cur.pop()
            cur.pop()
ans = 0
for (c, l) in cur: ans += l
print(ans)