# include<stdio.h>

 # include<string.h>

 const int N = ;

 const int INF = 0xffffff;

 int f[];    //f[i]表示总重量为i的硬币，价值为多少

 int p[N],w[N];

 int main()

 {

     int T;

     scanf("%d",&T);

     while (T--){

         int n,a,b,i,j;

         scanf("%d%d",&a,&b);

         f[] = ;    //表示重量为0的硬币价值为0

         for (i=;i<=b;i++) f[i]=INF;

         scanf("%d",&n);

         for (i=;i<=n;i++) scanf("%d%d",&p[i],&w[i]);

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

             for (j=w[i];j<=b-a;j++){

                 if (f[j-w[i]]+p[i]<f[j]) f[j]=f[j-w[i]]+p[i];

             }

         }

         if (f[b-a]==INF) printf("This is impossible.\n");

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

     }

     return ;

 }