#include<iostream>

 #include<cstdio>

 #include<cstring>

 #include<string>

 #include<algorithm>

 #include<cmath>

 #define INF 0x3f3f3f3f

 using namespace std;

 const int maxn=1e4+;

 int dp[maxn];

 int weight[];

 int money[];

 int main()

 {

     int T;

     scanf("%d",&T);

     while(T--)

     {

     //    memset(dp,0,sizeof(dp));

         int E,F;

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

         int v=F-E;

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

         {

             dp[i]=INF;

         }

         dp[]=;

         int n;

         scanf("%d",&n);

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

         {

             scanf("%d%d",&money[i],&weight[i]);

         }

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

         {

             for(int k=weight[i];k<=v;k++)

             {

                 dp[k]=min(dp[k],dp[k-weight[i]]+money[i]);

             }

         }

         if(dp[v]<INF)

         {

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

         }

         else

         {

             printf("This is impossible.\n");

         }

     }

     return ;

 }