#include <iostream>

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#define N 1000001

int dp[];

int main()

{

    int T,E,V,n;

    int w[],v[];

    scanf("%d",&T);

    while(T--)

    {

       scanf("%d%d",&E,&V);

       V=V-E;

       scanf("%d",&n);

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

       {

           scanf("%d%d",&v[i],&w[i]);

       }

       for(int i=;i<=V;i++)

         dp[i]=N;

         dp[]=;

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

       {

           for(int j=w[i];j<=V;j++)

           {

               if(dp[j-w[i]]+v[i]<dp[j])

                  dp[j]=dp[j-w[i]]+v[i];

           }

       }

       if(dp[V]==N) printf("This is impossible.\n");

       else printf("The minimum amount of money in the piggy-bank is %d.\n",dp[V]);

    }

    return ;

}