#include <stdio.h>

 #include <algorithm>

 #include <string.h>

 using namespace std;

 const int N =  + ;

 const int W =  + ;

 const int inf = 0x3f3f3f3f;

 int dp[W];

 int val[N],w[N];

 int main()

 {

     int T; scanf("%d",&T);

     while(T--)

     {

         int E, F;

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

         F -= E;

         int n;

         scanf("%d",&n);

         for(int i=;i<=n;i++) scanf("%d%d",val+i,w+i);

         memset(dp,inf,sizeof dp);

         dp[] = ;

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

         {

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

             {

                 dp[j] = min(dp[j], dp[j-w[i]] + val[i]);

             }

         }

         if(dp[F] == inf) puts("This is impossible.");

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

     }

     return ;

 }