#include<bits/stdc++.h>
using namespace std;
#define ll int
ll crr[10009],m,drr[10009],dp[10009],k,max1=600000000,h;
ll recur(ll g);
int d=0;
int main()
{
int t;
cin>>t;
while(t--)
{
ll i,x,y,j,a,b,s,g=0,flag=0;
cin>>a>>b;
k=b-a;
cin>>m;
for(i=0;i<m;i++)
{
cin>>x>>y;
crr[i]=y;
drr[i]=x;
/*if(y%2!=0)
{
flag=1;
}*/
}
for(i=0;i<=k;i++)
dp[i]=max1;
/* if(flag==0 && k%2!=0)
{
cout<<"This is impossible."<<endl;
continue;
}*/
if(k==0)
{
cout<<"The minimum amount of money in the piggy-bank is 0."<<endl;
}
else
{
recur(0);
if(dp[g]<600000000)
cout<<"The minimum amount of money in the piggy-bank is "<<dp[0]<<"."<<endl;
else
cout<<"This is impossible."<<endl;
}
}
}
ll recur(ll g)
{
if(g>k){
return max1;
}
if(g==k)
{
return 0;
}
if(dp[g]!=max1){
return dp[g];
}
else
{
for(ll i=0;i<m;i++)
{
dp[g]=min(drr[i]+recur(g+crr[i]),dp[g]);
}
return dp[g];
}
}
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