#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector<ll>;
ll Eulers_phi(ll n) {
    ll res = 0;
    ll N = n;
    vll P;
    for (ll p = 2; p * p <= N; p++) {
        if (N % p == 0) {
            P.push_back(p);
            while (N % p == 0)N /= p;
        }
    }
    if (N != 1)P.push_back(N);

    N = P.size();
    for(ll bit=0;bit< (1 << N);bit++) {
        ll k = 1, t = 0;
        for(ll i=0;i<N;i++) {
            if (bit & (1 << i)) {
                k *= P[i];
                t++;
            }
        }
        res += (t % 2 == 0 ? 1 : -1) * n / k;
    }
    return res;
}

ll gcd(ll a, ll b) {
    if (b == 0)return a;
    ll c = a;
    while (a % b != 0) {
        c = a % b;
        a = b;
        b = c;
    }
    return b;
}

ll num(ll p,ll N){//p/N以下の既約分数
    ll S=0;
    vll F(N+1,0);
    for (ll i = 1; i <= N; i++) {
        F[i] += (p* i) / N;//分母がiで mid/N以下の(既約とは限らない)分数の個数
        for (ll j = i * 2; j <= N; j += i)F[j] -= F[i]; //既約のみを取り出すため包除
        S += F[i];
    }
    return S;
}

int main() {
    ll T;
    cin>>T;
    while(T--){
        ll N, K;
        cin >> N >> K;
        ll L = 0;
        bool INV = 0;
        for (ll i = 2; i <= N; i++)L += Eulers_phi(i);
        if (K == L + 1) {
            cout << "1/1" << endl;
            continue;
        }
        if(K>2*L+1){
            cout<<-1<<endl;
            continue;
        }
        if (K > L + 1) {
            INV = 1;
            K=2*L-K+2;
        }
        ll l = 0, r = N;
        while (r - l > 1)(num((r + l)/2,N)<=K?l:r)=(r + l) / 2;
        vll F(N + 1, 0);
        K-=num(l,N);
        vector<pair<ll,ll>> P;
        for(ll i=1;i<=N;i++){
            ll a=(l*i+N-1)/N;
            while(a*N<i*(l+1)){
                if(gcd(a,i)==1)P.push_back({a,i});
                a++;
            }
        }
        sort(P.begin(),P.end(),[](auto const& lhs, auto const& rhs) {
            return lhs.first*rhs.second < rhs.first*lhs.second;
        });

        if(INV)swap(P[K].first,P[K].second);
        cout<<P[K].first<<"/"<<P[K].second<<endl;
    }
}