def binary_to_decimal(binary):
decimal = 0
power = 0

while binary > 0:
rem = binary % 10
decimal += rem * (2 ** power)
binary = binary // 10
power += 1
return decimal

binary_number = int(input("Введите двоичное число: "))
decimal_number = binary_to_decimal(binary_number)
print("Число в десятичной системе счисления:", decimal_number)