from collections import deque

S = input()
D = []
for i in range(len(S)):
    if(S[i]=="<"):
        D.append("<")
    if(S[i]=="="):
        D.append("=")
    if(S[i]==">"):
        D.append(">")
        # "="が1つ以上存在するか
        bl1 = False
        # "<"ではじまるか
        bl2 = False
        j = len(D) - 1

        for _ in range(len(S)):
            j -= 1
            # 範囲外参照をしない
            if(j < 0):
                bl2 = False
                break
            
            if(D[j] == "<"):
                bl2 = True
                break
            elif(D[j] == ">"):
                bl2 = False
                break
            
            # "="があるか判定
            if(D[j] == "="):
                bl1 = True
        
        if(bl1 and bl2):
            for _ in range(len(D)-j):
                D.pop()
    
print(len(D))