#include <bits/stdc++.h>
using namespace std;
template <typename T, typename U>
inline void smin(T &a, const U &b) {
  if (a > b) a = b;
}
template <typename T, typename U>
inline void smax(T &a, const U &b) {
  if (a < b) a = b;
}
template <class T>
inline void gn(T &first) {
  char c, sg = 0;
  while (c = getchar(), (c > '9' || c < '0') && c != '-')
    ;
  for ((c == '-' ? sg = 1, c = getchar() : 0), first = 0; c >= '0' && c <= '9';
       c = getchar())
    first = (first << 1) + (first << 3) + c - '0';
  if (sg) first = -first;
}
template <class T1, class T2>
inline void gn(T1 &x1, T2 &x2) {
  gn(x1), gn(x2);
}
int power(int a, int b, int m, int ans = 1) {
  for (; b; b >>= 1, a = 1LL * a * a % m)
    if (b & 1) ans = 1LL * ans * a % m;
  return ans;
}
const int inf = 1e9;
long long calc(int k, int m) {
  long long tot = (long long)k * m;
  long long ans = 1;
  long long now = 1;
  for (int t = 1; tot && t <= k; t++) {
    if (tot / (k - t + 1) >= now) {
      tot -= now * (k - t + 1);
      now = now * (k - t + 1) / t;
      ans += now;
      if (ans >= inf) return ans;
    } else
      return ans + tot / t;
  }
  return ans;
}
int main() {
  int T, n, m;
  for (gn(T); T--;) {
    gn(n, m);
    int st = -1, ed = n - 1;
    while (ed - st > 1) {
      int mid = st + ed >> 1;
      if (calc(mid, m) < n)
        st = mid;
      else
        ed = mid;
    }
    printf("%d\n", ed);
  }
  return 0;
}
