#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int w1,w2,wi,t,k,f[10002],v[510],w[510];
int main()
{
    scanf("%d",&t);
    while(t--)
    {
        memset(f,0x3f,sizeof(f));
        f[0]=0; //**
        scanf("%d%d",&w1,&w2);
        wi=w2-w1;
        scanf("%d",&k);
        for(int i=1;i<=k;i++)
        scanf("%d%d",&v[i],&w[i]);
        for(int i=1;i<=k;i++)
        for(int j=w[i];j<=wi;j++)
        f[j]=min(f[j],f[j-w[i]]+v[i]);
        if(f[wi]==0x3f3f3f3f)
        printf("This is impossible.\n");
        else
        printf("The minimum amount of money in the piggy-bank is %d.\n",f[wi]);
    }
    return 0;
}