#include<bits/stdc++.h>

#define MAX 1000008

using namespace std;

bool flag[MAX];

int primes[MAX];

int cnt,a[2000];



void sieve(int n)

{

cnt=0;

primes[cnt++] = 2;

for(int i=3; i<=n; i+=2)

{

if(flag[i] == 0)

{

primes[cnt++] = i;

if(i <= n/i)

{

for(int j=i*i; j<=n; j+=i*2)

flag[j] = 1;

}

}

}

return ;

}



int main()

{

    int n,u,l,pos,c,count,max,k,result,j,i;

    sieve(MAX);

    cin>>n;

    while(n--)

    {

    pos=0;

        cin>>l>>u;

for(int i=0;i<cnt;i++)

{

if(primes[i]>=l)

break;

pos++;   

}

memset(a, 0, sizeof(a));

for(j=pos;j<cnt and primes[j+1]<=u;j++)



        //a[primes[j+1] - primes[j]]++;

    {

            a[primes[j+1]-primes[j]]++;

        }

        count=0, max=0;

        for(k=0; k<120; k++)

        {

               

            if(a[k]>max)

            {

                result=k;

                max=a[k];

                count=1;

            }

            else if(max==a[k])

                count++;

        }

        if(count==1)

        {

            printf("The jumping champion is %d\n", result);

        }

        else

        {

            printf("No jumping champion\n");

        }

    }

    return 0;

}