包对AC

#include<queue>
#include<math.h>
#include<stdio.h>
#include<iostream>
#include<vector>
#include<iomanip>
#include<string.h>
#include<algorithm>
#include<cmath>
#include<cstdio>
#include<utility>
#include<cstring>
#include<stack>
#include<fstream>
#include<string>
using namespace std;
typedef long long ll;
const int N = 1e5 + 10;
const int INF = 0x3f3f3f3f;
string s;
long long c , x , ans = 0 , p = 1;
int main()
{
	cin>>s;
	c = s.size() - 1;
	for ( int i = c ; i >= 0 ; i-- )
	{
		if ( s[i] >= '0' && s[i] <= '9' )
		{
			x = s[i] - '0';
		}
		else if ( s[i] >= 'A' && s[i] <= 'Z' )
		{
			x = s[i] - 'A' + 10;
		}
		else 
		{
			x = s[i] - 'a' + 10;
		}
		ans += x * p;
		p *= 16;
	}
	cout << ans;
	return 0;
}