from itertools import product
d = {'ballot1': ['a','b','a','a','b','a','a','b'],
     'ballot1_x':['c','c','d','d','a','a','a','a']}
df1=pd.DataFrame(d)
for i in product(set(df1['ballot1']), set(df1['ballot1_x'])):
    print(str(i[0])+str(i[1]))

a  b
c 1  1
d 2  0
a 2  2