#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector<ll>;
#define rep(i,s,t,p) for(int i=s;i<t;i+=p)
vll PR;

void mobius(vll&A){
    ll N=A.size();
    for (auto p:PR) {
        if(p>N)break;
        for(int i=(N-1)/p;i>=1;i--) {
            A[p*i]-=A[i];
        }
    }
    return;
}

ll b=(1ll<<40);
ll num(ll p,ll N){//p/b以下分母がN以下の既約分数
    ll S=0;
    vll F(N+1,0);
    rep(i,1,N+1,1){
        F[i]+=(p*i)/b;//分母がiで mid/N以下の(既約とは限らない)分数の個数
    }
    mobius(F);
    rep(i,1,N+1,1)S+=F[i];
    return S;
}

int main() {
    ll NINF=3e5+1,T,N,K;
    vector<bool> P(NINF,1);
    rep(i,2,NINF,1)if(P[i]){
        PR.push_back(i);
        rep(j,2*i,NINF,i)P[j]=0;
    }
    cin>>T;
    while(cin>>N>>K){
        ll L=num(b,N)-1;
        bool INV=0;
        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=b+1;
        while(r-l>1)(num((r+l)/2,N)<K?l:r)=(r+l)/2;
        vll F(N+1,0);
        pair<ll,ll> P;
        rep(i,1,N+1,1){
            ll a=(r*i)/b;
            if(gcd(a,i)==1)if(a*b>=l*i)P={a,i};
        }
        if(INV)swap(P.first,P.second);
        cout<<P.first<<"/"<<P.second<<endl;
    }
}