S = input()

left = []
ans = []
for i in range(len(S)):
    if(S[i] == "<"):
        left.append(i)
        ans.append("<")
    elif(S[i] == "="):
        ans.append("=")
    else:
        if(len(left) > 0):
            if(ans[-1] == "="):
                while(True):
                    if(ans[-1] == "="):
                        ans.pop()
                    elif(ans[-1] == "<"):
                        ans.pop()
                        left.pop()
                        break
            else:
                left = []
                ans.append(">")
        else:
            ans.append(">")

print(len(ans))