#include<stdio.h>
int main(){
	long long n,k,i,j,t,s,ok,q,d,p,v[8];
	freopen("divprim.in","r",stdin);
	freopen("divprim.out","w",stdout);
	scanf("%lld",&t);
	for(i=0;i<t;++i){
		scanf("%lld",&n);
		scanf("%lld",&k);
		ok=1;
		for(j=n;j>=0 && ok;--j){
			s=0;
			if(j%2==0)
				s++;
			ok=1;
			d=0;
			for(q=3;q<=j;q+=2){
				for(p=0;p<d;++p)
					if(q%v[p]==0)
						ok=0;
				if(j%q==0 && ok){
					s++;
					v[d]=q;
					d++;
				}
				ok=1;
			}
			if(k==s){
				printf("%lld\n",j);
				ok=0;
			}
		}
		if(ok!=0)
			printf("0\n");
	}
	fclose(stdin);
	fclose(stdout);
	return 0;
}