#include<iostream>
#include<string>
using namespace std;
int main()
{
int a;
char * str = new char[256];
cin >> a;
cin >> str;
int index = 0;
while (a != 0 && index < strlen(str))
{
if (a & 0x01)
cout << str[index];
a >>= 1;
index++;
}
delete str;
return 0;
}