#include<stdio.h>

#define INF 100000

int min0(int i,int j)

{

if(i==0)

return j;

else

{

if(i<j)

return i;

else

return j;

}

}

int main()

{

int t;

int e,f;

scanf("%d",&t);

while(t--)

{

scanf("%d%d",&e,&f);

int *arr=(int*)calloc(sizeof(int),f-e+1);

int n;

scanf("%d",&n);

int p[n],w[n];

int i,j;

for(i=0;i<n;i++)

{

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

if(w[i]<=f-e)

arr[w[i]]=min0(arr[w[i]],p[i]);

}

for(i=1;i<=f-e;i++)

{

int min=arr[i];

for(j=1;j<=i/2;j++)

{

if(arr[j]!=0&&arr[i-j]!=0)

min=min0(min,arr[j]+arr[i-j]);

}

arr[i]=min;

}

if(arr[f-e])

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

else

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

}

return 0;

}