#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }
#define COLOR(s) ("\x1b[" s "m")



int main() {
  for (int numCases; ~scanf("%d", &numCases); ) { for (int caseId = 1; caseId <= numCases; ++caseId) {
    Int N, K;
    scanf("%lld%lld", &N, &K);
    
    /*
    for (Int u = 1; ; ) {
      const Int v = u + (u + (K-1) - 1) / (K-1);
      if (v > N) {
        printf("%lld\n", u);
        break;
      }
      u = v;
    }
    */
    Int ans = 0;
    for (Int u = 1; ; ) {
      const Int d = (u + (K-1) - 1) / (K-1);
      /*
        min m s.t.
          ceil((u + d m) / (K-1)) > d
          u/d + m > K-1
        go m steps
      */
      const Int m = max((u + d - 1) / d - K, 1LL);
      if (u + m * d > N) {
        ans = u + ((N - 1) - u) / d * d;
        break;
      }
      u += m * d;
    }
    printf("%lld\n", ans);
  }
#ifndef LOCAL
  break;
#endif
  }
  return 0;
}