1 #include<stdio.h>
  2 #include<string.h>
  3 #include<math.h>
  4 
  5 int a[1000050],b[1000000],k,f[1000050],s[1000050][10];
  6 
  7 int Sieve(int n)
  8 {
  9   a[1]=0;k=0;a[0]=0;
 10            for (int i = 2; i <= n; i++)
 11                 a[i] =1;
 12            for (int i = 2; i <= sqrt(n); i++)
 13            {
 14                if (a[i])
 15                    for (int j = i; j*i <=n; j++)
 16                         a[j * i] = 0;
 17            }
 18            for (int i = 0; i <= n; i++)
 19            {
 20                if (a[i]==1)
 21                {
 22                     k++;
 23                     b[k]=i;
 24                }
 25            }
 26 }
 27 
 28 int gcd(int a,int b) 
 29 { 
 30     if(a<b) 
 31         return gcd(b,a); 
 32     else if(b==0) 
 33         return a; 
 34     else
 35         return gcd(b,a%b); 
 36 } 
 37 
 38 int main()
 39 {
 40     int T;
 41     int i,j,k;
 42     Sieve(1000000);
 43     memset(f,0,sizeof(f));
 44     for(i=2;i<=1000000;i++)
 45     {
 46         int x=i;
 47         k=1;
 48         while(1)
 49         {
 50           if(x==1)
 51           {
 52             break;
 53           }
 54           if(a[x]==1)
 55           {
 56             f[i]++;
 57             break;
 58           }
 59 
 60           if(x%b[k]==0)
 61           {
 62             f[i]++;
 63             while(x%b[k]==0)
 64             {
 65               x=x/b[k];
 66             }
 67           }
 68           k++;
 69         }
 70         //printf("%d ",f[i]);
 71     }
 72     memset(s,0,sizeof(s));
 73     for(i=1;i<=1000000;i++)
 74     {
 75       for(j=1;j<=7;j++)
 76         s[i][j]=s[i-1][j];
 77       s[i][f[i]]++;
 78     }
 79     scanf("%d",&T);
 80     int l,r;
 81     int num[15];
 82     while(T--)
 83     {
 84         memset(num,0,sizeof(num));
 85         scanf("%d %d",&l,&r);
 86         for(i=1;i<=8;i++)
 87           num[i]=s[r][i]-s[l-1][i];
 88         int ma=0;
 89         for(i=10;i>=1;i--)
 90         {
 91           if(num[i]>0)
 92           {
 93             if(num[i]>=2)
 94             {
 95               if(i>ma)
 96                 ma=i;
 97             }
 98             else
 99             {
100               for(j=i-1;j>=1;j--)
101               {
102                 if(num[j]>0)
103                   if(gcd(i,j)>ma)
104                     ma=gcd(i,j);
105               }
106             }
107 
108           }
109         }
110         printf("%d\n",ma);
111     }
112     return 0;
113 }