def convert(num, to_base=10, from_base=10):
txt = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
dd = 0
rrr = []
for _ in range(len(num)):
dd += int(txt.find(num[_], 0,35))*from_base**(len(num)-1-_)
while dd != 0:
rr1 = int(dd) // to_base
rr2 = int(dd) % to_base
rrr.append(txt[rr2])
dd = rr1
ss = ''.join(rrr[::-1])
return ss