int knapSack(int W, int wt[], int val[], int n) 
{ 
   if(W==0 || n==0) return 0;
   if(wt[n-1]<=W){
       return max(
         val[n-1] + knapSack(W-wt[n-1], wt, val, n-1), 
         knapSack(W, wt, val, n-1)
       );
   }
   else {
       return knapSack(W, wt, val, n-1);
   }
}