import java.io.* ;
import java.util.* ;
public class drop {
   public static void main(String[] args) throws Exception {
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in)) ;
      while (true) {
         String[] f = br.readLine().split(" ") ;
         int n = Integer.parseInt(f[0]) ;
         int k = Integer.parseInt(f[1]) ;
         if (n == 0)
            break ;
         long[] nn = new long[n], dd = new long[n], w = new long[n] ;
         f = br.readLine().split(" ") ;
         for (int i=0; i<n; i++)
            nn[i] = Long.parseLong(f[i]) ;
         f = br.readLine().split(" ") ;
         for (int i=0; i<n; i++)
            dd[i] = Long.parseLong(f[i]) ;
         int r = 0 ;
         for (int b=64; b>0; b>>=1) {
            for (int i=0; i<n; i++)
               w[i] = nn[i] * 200 - dd[i] * (2*(r+b)-1) ;
            Arrays.sort(w) ;
            long s = 0 ;
            for (int i=k; i<n; i++)
               s += w[i] ;
            if (s >= 0)
               r += b ;
         }
         System.out.println(r) ;
      }
   }
}