convert_base=lambda N,A,B,P=0:(lambda v,n:''.join(map(lambda x:chr(x+(x>9 and 55
or 48)),[(v//n**k)%n for k in xrange(4*len(str(v)))]))[::-1].lstrip('0'))(reduce
(lambda x,y:x*A+ord(y.upper())-(y<'A'and 48 or 55),str(N),0),B).zfill(P or 1)#:)