import sys dic={'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} for line in sys.stdin: a = list(line.split()[0][2:]) num = 0 a.reverse() for i in range(len(a)): num += dic[a[i]]*(16**(i)) print(num)