print(bin(13))
print(bin(255))
print(int("1101", 2))
print(int("11111111", 2))

def to_binary(n):
    if n == 0:
        return "0"
    result = ""
    while n > 0:
        result = str(n % 2) + result
        n = n // 2
    return result

print(to_binary(13))
print(to_binary(42))
