public static void Main()
{
SieveOfEratosthenes sieve = new SieveOfEratosthenes(100000);
sieve.Run();
int[] q = new int[100010];
for (int i = 1; i <= 100000; i++)
{
if (sieve.IsPrime(i) && sieve.IsPrime((i + 1) / 2))
{
q[i] = q[i - 1] + 1;
}
else
{
q[i] = q[i - 1];
}
}
int Q = NextInt();
for (int i = 0; i < Q; i++)
{
int a = NextInt() - 1, b = NextInt();
Console.WriteLine(q[b] - q[a]);
}
}
public static void Main()
{
int N = Cin <int>();
SieveOfEratosthenes soe = new SieveOfEratosthenes(1000010);
soe.Run();
Console.WriteLine(soe.IsPrime(N) ? "YES" : "NO");
}
public static bool IsPrime(this int value)
{
return(SieveOfEratosthenes.IsPrime(value));
}
