S=input()

X=[]

for s in S:
    if X==[]:
        X.append([s,1])
    else:
        if s=="=" and X[-1][0]==s:
            X[-1][1]+=1
        else:
            X.append([s,1])

Y=[]
for s,ko in X:
    if s==">" and len(Y)>=2 and Y[-1][0]=="=" and Y[-2][0]=="<":
        Y=Y[:-2]
    else:
        Y.append([s,ko])

ANS=0
for s,ko in Y:
    ANS+=ko

print(ANS)