# http://c...content-available-to-author-only...e.com/a/85414/34718
L=[1]
i=0
n=input()
while len(L)<3*n:L+=[2*L[i]+1,3*L[i]-1];i+=1
print sorted(set(L))[n]
IyBodHRwOi8vYy4uLmNvbnRlbnQtYXZhaWxhYmxlLXRvLWF1dGhvci1vbmx5Li4uZS5jb20vYS84NTQxNC8zNDcxOAoKTD1bMV0KaT0wCm49aW5wdXQoKQp3aGlsZSBsZW4oTCk8MypuOkwrPVsyKkxbaV0rMSwzKkxbaV0tMV07aSs9MQpwcmludCBzb3J0ZWQoc2V0KEwpKVtuXQ==