#include <bits/stdc++.h>   using namespace std;   int32_t main() {     ios::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     ;     long long n, p;     cin >> n >> p;     long long ans = 5 * 5000000;     for (long long i = 1; i <= 5000000; i++) {       long long left = n - p * i;       if (left < 1)         continue;       else {         long long k = __builtin_popcount(left);         if (k <= i and left >= i) {           cout << i;           return 0;         }       }     }     cout << -1;     return 0;   }   