#include<iostream>

#include<cstdio>

#include<cstring>

using namespace std;

const int INF = ;

int dp[INF],val[INF],we[INF];

int main(void)

{

    int t,n,i,j,m,st,ed,tp;

    cin>>t;

    while(t--)

    {

        cin>>st>>ed;

        cin>>n;

        tp=ed-st;

        for(i=;i<n;i++) cin>>val[i]>>we[i];

        memset(dp,INF,sizeof(dp));

        dp[]=;

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

        {

            for(j=we[i];j<=tp;j++)

            {

                dp[j]=min(dp[j],dp[j-we[i]]+val[i]);

            }

        }

        //cout<<"--"<<num[tp]<<endl;

        if(dp[tp]!=dp[]) printf("The minimum amount of money in the piggy-bank is %d.\n",dp[tp]);

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

    }

    return ;

}