def fun(num1,num2):
#num1 type str
#num2 type str
a = map(int,list(reversed(num1)))
b = map(int,list(reversed(num2)))
result = [0]*(len(a) + len(b))
for ia,va in enumerate(a):
c = 0
for ib,vb in enumerate(b):
tmp = va*vb + c + result[ia+ib]
result[ia+ib] = tmp % 10
c = tmp / 10
result[ia+ib+1] = c
result = result[::-1]
print result
fun('254954058045047604584','25343434358748574957945794759475948759475945794')