def dec_to_bin(n):
    ans = 0
    f = 0
    n = int(n)
    while (n != 0):
        ans += ((10 ** f) * (n % 2))
        n = n // 2
        f += 1
    return ans

def bin_to_dec(n):
    ans = 0
    f = 0
    n = int(n)
    while (n != 0):
        ans += ((2 ** f) * (n % 10))
        n = n // 10
        f += 1
    return ans

def oct_to_dec(n):
    ans = 0
    f = 0
    n = int(n)
    while (n != 0):
        ans += ((8 ** f) * (n % 10))
        n = n // 10
        f += 1
    return ans

def hex_to_dec(n):
    ans = 0
    f = 0
    n = int(n)
    while(n != 0):
        x = n % 10
        x2 = 0
        p2 = 0
        while(x > 0):
            x2 += (x % 2) * (10 ** p2)
            x = x // 2
            p2 += 1
        ans += x2 * (1000 ** f)
        n = n // 10
        f += 1
    print(ans)
    return bin_to_dec(ans) * 2