#include
#include
#include
using namespace std;
const int INF=0x30303030;
const int SIZE=+;
int w[SIZE];
int v[SIZE];
int dp[SIZE];
int main()
{
int T;
scanf("%d",&T);
while(T--)
{
int E,F;
scanf("%d %d",&E,&F);
int vol=F-E;

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

    for(int i=;i<N;i++)  
    {  
        scanf("%d %d",&v\[i\], &w\[i\]);  
    }    

    memset(dp,INF,sizeof(dp));  
    dp\[\]=;

    for(int i=;i<N;i++)  
        for(int j=w\[i\];j<=vol;j++)  
            if(dp\[j\]>dp\[j-w\[i\]\]+v\[i\])  
                dp\[j\]=dp\[j-w\[i\]\]+v\[i\];

    if(dp\[vol\]==INF)  
        printf("This is impossible.\\n");  
    else  
        printf("The minimum amount of money in the piggy-bank is %d.\\n",dp\[vol\]);

}

return ;  

}