S = input()
L = [S[a] for a in range(len(S))]
K = True

while K:
    dame = 0
    i = -1
    k = 0
    for a in range(len(L)):
        if L[a] == "<":
            i = a
            k = 0
        elif L[a] == "=":
            if i != -1:
                k = 1
        elif L[a] == ">":
            if i != -1 and k == 1:
                if a == len(L)-1:
                    L = L[:i]
                else:
                    L = L[:i] + L[a+1:]
                break
            else:
                i = -1
                k = 0
        if a == len(L)-1:
            dame = 1
    if dame >= 1:
        K = False

print(len(L))