#include <iostream>

#include <cstdio>

#include <cstring>

#include <cstdlib>

#include <cmath>

#include <map>

#include <algorithm>

using namespace std;

long long dp[];

int money[], weight[];

int main()

{

    int t;

    scanf("%d",&t);

    while(t--)

    {

        int w1,w2;

        scanf("%d%d",&w1,&w2);

        int all = w2 - w1;

        dp[] = ;

        for(int i = ;i <= all;i++)

            dp[i] = ;

        int kind;

        scanf("%d",&kind);

        for(int i = ;i < kind;i++)

        {

            scanf("%d%d",&money[i],&weight[i]);

        }

        for(int i = ;i < kind;i++)

        {

            for(int j = weight[i]; j <= all;j++)

            {

                dp[j] = min(dp[j],dp[j-weight[i]] + money[i]);

            }

        }

        if(dp[all] == )

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

        else printf("The minimum amount of money in the piggy-bank is %lld.\n",dp[all]);

    }

    return ;

}