#include<iostream>
using namespace std;
#define M 501
#define INF 0x7fffffff
struct Node
{
int w , p;
}nod[M];
int dp[10001];
int main()
{
int t , n;
int w , wt , pt;
int i , j;
scanf( "%d" , &t );
while( t-- )
{
scanf( "%d %d" , &w , &wt );
w = wt - w;
scanf( "%d" , &n );
for( i = 0 ; i < n ; ++i )
{
scanf( "%d %d" , &pt , &wt );
nod[i].w = wt;
nod[i].p = pt;
}
for( i = 1 ; i <= w ; ++i )
{ dp[i] = INF; }
dp[0] = 0;
for( i = 0 ; i < n ; ++i )
{
for( j = nod[i].w ; j <= w ; ++j )
{
if( dp[j - nod[i].w] != INF )
{
pt = dp[j - nod[i].w] + nod[i].p;
dp[j] = dp[j] < pt ? dp[j] : pt;
}
}
}
if( dp[w] == INF )
{ printf( "This is impossible./n" ); }
else
{ printf( "The minimum amount of money in the piggy-bank is %d./n" , dp[w] ); }
}
return 0;
}