#include <iostream>
using namespace std;
int main()
{
long long n,b;
cin >> n >> b;
if ((n&(1<<b))!=0) cout << n-(1<<b);
else cout << n;
}
I2luY2x1ZGUgPGlvc3RyZWFtPgp1c2luZyBuYW1lc3BhY2Ugc3RkOwppbnQgbWFpbigpCnsKICAgIGxvbmcgbG9uZyBuLGI7CiAgICBjaW4gPj4gbiA+PiBiOwogICAgaWYgKChuJigxPDxiKSkhPTApIGNvdXQgPDwgbi0oMTw8Yik7CiAgICBlbHNlIGNvdXQgPDwgbjsKfQ==