题解 | #进制转换#

data = input().upper() 
data_arr = data[::-1]
data_arr1 = data_arr[0:len(data_arr)-2:1]

data_dict = {'0':0,'1':1,'2':2,'3':3,'4':4,'5':5,'6':6,'7':7,'8':8,'9':9,'A':10,'B':11,'C':12,'D':13,'E':14,'F':15}
num = 0
for word_index in range(len(data_arr1)):
    word = data_arr1[word_index]
    num += data_dict.get(word)*(16**word_index)
print(num)