def Run_Length(lst):
    run_length=[]
    if lst:
        prev=lst[0]
        cnt=1
        for x in lst[1:]:
            if x==prev:
                cnt+=1
            else:
                run_length.append((prev,cnt))
                prev=x
                cnt=1
        run_length.append((prev,cnt))
    return run_length

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