poj1384

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;
int v[501],w[501],d[10001],n;
bool visi[10001];

int solve(int s)
{
    if(visi[s])
        return d[s];
    visi[s] = true;
    for(int i=1;i<=n;++i)
        if(s>=w[i]) d[s] = min(d[s],v[i]+solve(s-w[i]));
    return d[s];
}

int main()
{
    int t,e,f;
    scanf("%d",&t);
    while(t--)
    {
        for(int i=1;i<=10001;++i)
            d[i] = (1<<30);
        memset(visi,0,sizeof(visi));
        visi[0]=true;d[0]=0;
        scanf("%d %d",&e,&f);
        int s=f-e,ans;
        scanf("%d",&n);
        for(int i=1;i<=n;++i)
            scanf("%d %d",&v[i],&w[i]);
        if((ans=solve(s))<(1<<30))
            printf("The minimum amount of money in the piggy-bank is %d.\n",ans);
        else
            printf("This is impossible.\n");
    }

    return 0;
}