#include < iostream >
using   namespace  std;

int  n,v;
int  f[ 10010 ];
int  main()
{
     int  t;
    scanf( " %d " , & t);
     while (t -- ){
         int  v1;
        scanf( " %d%d%d " , & v1, & v, & n);
        v -= v1;
        memset(f, 0x7F , sizeof (f));
        f[ 0 ] = 0 ;
         for ( int  i = 1 ;i <= n; ++ i){
             int  w,c;
            scanf( " %d%d " , & c, & w);
             for ( int  j = w;j <= v; ++ j)
                 if (f[j] > f[j - w] + c)
                    f[j] = f[j - w] + c;
        }
         if (f[v] >= 0xFFFFFFF ) printf( " This is impossible.\n " );
         else  printf( " The minimum amount of money in the piggy-bank is %d.\n " ,f[v]);
    }
     return   0 ;
}