#include<bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")

namespace po167{
//out F_{n,k}
//O(Nlog(N))
//N<2^{21}
//F_{n,0}=={0,1}
//if k==-1 -> return {n,len(F_{n})}
//https://atcoder.jp/contests/joisc2008/submissions/40395171
std::pair<long long,long long> Farey_Sequence(long long n,long long k){
	std::vector<long long> p(n+1,1);
	for(int i=n;i>=1;i--){
		for(int j=i*2;j<=n;j+=i) p[i]-=p[j];
	}
	long long lim=0;
	for(long long i=1;i<=n;i++) lim+=i*p[i];
	if(k==-1) return {n,lim};
	if(k==0) return {0,1};
	if(lim==k) return {1,1};
	if(lim<k) return {-1,-1};
	long long M=n*n;
	long long l=0,r=M-1;
	while(r-l>1){
		long long med=(l+r)/2;
		long long tmp=0;
		for(long long i=1;i<=n;i++) tmp+=(p[i]*((i*med)/M));
		if(tmp<k) l=med;
		else r=med;
	}
	for(long long i=2;i<=n;i++){
		long long x=((long long)(i)*r)/M;
		if(i*l<x*M){
			return {x,i};
		}
	}
	assert(false);
}
}

using namespace std;
using ll=long long;
#define rep(i,a,b) for (ll i=a;i<b;i++)

pair<int,int> solve_yuki_2262(long long N,long long K){
	auto tmp=po167::Farey_Sequence(N,-1);
	if(tmp.second*2ll-1<K){
		return {-1,-1};
	}
	bool rev=0;
	if(tmp.second<K){
		rev=1;
		K=tmp.second*2ll-K;
	}
	tmp=po167::Farey_Sequence(N,K);
	if(rev) swap(tmp.first,tmp.second);
	return tmp;
}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int T;
	cin>>T;
	rep(i,0,T){
		ll N,K;
		cin>>N>>K;
		auto ans=solve_yuki_2262(N,K);
		if(ans.first==-1) cout<<"-1\n";
		else cout<<ans.first<<"/"<<ans.second<<"\n";
	}
}