'''
base1, exp1 = 7777, 290
base2, exp2 = 777, 29
base3, exp3 = 77, 2
const = 7
result = (base1 ** exp1) - (base2 ** exp2) + (base3 ** exp3) - const
base_20 = ""
temp = result
while temp > 0:
base_20 = str(temp % 20) + base_20
temp //= 20
unique_digits = set(base_20)
len(unique_digits)
'''
Вывод: 10