题解 | 进制转换

def test(s):
    n = len(s)
    help_map = {'0': 0, '1': 1, '2': 2, '3': 3, '4': 4, 
                '5': 5, '6': 6, '7': 7, '8': 8, '9': 9,
                'A': 10, 'B': 11, 'C': 12, 'D': 13, 
                'E': 14, 'F': 15}
    res = 0
    for i in range(n-1, 1, -1):
        res += help_map[s[i]] * (16 ** (n - (i + 1)))
    return res

s = input()
res = test(s)

print(res)