#include <stdio.h>
char a[2000001];
void ciur()
{ long long i,j;
	for (i=2;i<=2000000;i++)
		if (a[i]==0)
			{
			j=1;
			while(i*j<=2000000)
				{
				a[i*j]++;
				j++;
				}
			}
}

int main()
{ long long n,i,x,j,y;
FILE*f=fopen("divprim.in","r");
FILE*g=fopen("divprim.out","w");
ciur();
fscanf(f,"%lld",&n);
for (i=1;i<=n;i++)
	{
	fscanf(f,"%lld",&x);
	fscanf(f,"%lld",&y);;
	while(a[x]!=y && x>1) x--;
	if (x==1) fprintf(g,"0\n");
	else fprintf(g,"%lld\n",x);
	}
return 0;
}