#include <iostream>

 #include <cstring>

 #include <cstdio>

 using namespace std;

 const int maxn = 1e4 + ;

 const int INF = ;    // 这个INF一定要好大好大好大！！！！

 int w[maxn], v[maxn];

 int dp[maxn];

 int main()

 {

     int T, n, m, E, F;

     while (scanf("%d", &T) != EOF)

     {

         while (T--)

         {

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

             int Maxweight = F - E;

             scanf("%d", &n);

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

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

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

                 dp[i] = INF;

             dp[] = ;

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

             {

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

                 {

                     dp[j] = min(dp[j], dp[j-w[i]]+v[i]);  // 选取币值最少的

                 }

             }

             if (dp[Maxweight] != INF)

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

             else

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

         }

     }

     return ;

 }