#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define inf 0x3f3f3f3f
int w[510],v[510],f[10010];
int main()
{
    int T,v1,v2,n;
    scanf("%d",&T);
    while(T--){
        scanf("%d%d",&v1,&v2);
        scanf("%d",&n);
        int vn=v2-v1;
        for(int i=0;i<=vn;i++)
            f[i]=inf;
        f[0]=0;
        for(int i=1;i<=n;i++)
            scanf("%d%d",&w[i],&v[i]);
        for(int i=1;i<=n;i++){
            for(int j=v[i];j<=vn;j++)
                f[j]=min(f[j],f[j-v[i]]+w[i]);
        }
        if(f[vn]!=inf)
            printf("The minimum amount of money in the piggy-bank is %d.\n",f[vn]);
        else
            printf("This is impossible.\n");
    }
}