#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
// constexpr int MOD = 1000000007;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

int main() {


  int t; cin >> t;
  while (t--) {
    int n; ll k; cin >> n >> k;
    const auto f = [&](const ll k) -> ll {
      // ll res = 0;
      // for (int num = 1; num <= n; ++num) {
      //   for (int den = 1; den <= n; ++den) {
      //     if (gcd(num, den) == 1 && num * n * n <= k * den) ++res;
      //   }
      // }
      // return res;
      vector<ll> g(n + 1, 0);
      for (int den = 1; den <= n; ++den) {
        g[den] += k * den / n / n;
        for (int i = den * 2; i <= n; i += den) {
          g[i] -= g[den];
        }
      }
      // cout << k << ": ";
      // REP(i, n + 1) cout << g[i] << " \n"[i == n];
      return reduce(ALL(g), 0LL);
    };
    const ll nmt1 = f(1LL * n * n);
    if (nmt1 == k) {
      cout << "1/1\n";
      continue;
    }
    if (k >= nmt1 * 2) {
      cout << "-1\n";
      continue;
    }
    bool k_is_large = false;
    if (nmt1 < k) {
      k = nmt1 * 2 - k;
      k_is_large = true;
    }
    ll lb = 0, ub = 1LL * n * n - 1;
    while (ub - lb > 1) {
      const ll mid = midpoint(lb, ub);
      (f(mid) >= k ? ub : lb) = mid;
    }
    for (int den = 1; den <= n; ++den) {
      const ll num = ub * den / n / n;
      if ((ub - 1) * den < num * n * n) {
        if (k_is_large) {
          cout << den << '/' << num << '\n';
        } else {
          cout << num << '/' << den << '\n';
        }
        break;
      }
    }
  }
  return 0;
}