#include <cstdio>
#include <iostream>
#include <string>
#include <cmath>
using namespace std;
int main() {
long long x = 0;
int y;
int i = 0;
string s;
cin >> s >> y;
for (auto it = s.begin(); it != s.end(); it++)
{
char c = *it;
if (c >= 'A' && c <= 'Z')
x += pow(y, i) * (c - 'A' + 10);
else
x += pow(y, i) * (c - '0');
i++;
}
cout << x;
return 0;
}
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