#include <cstdio>
#include <iostream>
#include <cmath>
using namespace std;
#define INF 0x7ffffff
#define maxn 10000+5
int dp[maxn];
int T,n,w1,w2,P,W;
int main()
{
cin>>T;
while(T--)
{
cin>>w1>>w2;
for(int i=1; i<=w2-w1; i++)
dp[i]=INF;
dp[0]=0;
//cout<<dp[1]<<endl;
cin>>n;
for(int i=0; i<n; i++)
{
cin>>P>>W;
for(int i=W; i<=w2-w1; i++)
dp[i]=min(dp[i-W]+P,dp[i]);
}
if(dp[w2-w1]==INF) cout<<"This is impossible.\n";
else cout<<"The minimum amount of money in the piggy-bank is "<<dp[w2-w1]<<"."<<endl;
///cout<<endl;
}
}