#include <stdio.h>
int find(int x[],int t);
{
 int left=0,mid,right=14;
 while(left<=right)
 {
  mid=(left+right)/2;
  if(t==x[mid]){return mid;}
   else
   {
    if(t>x[mid]){left=mid+1;}
    else{right=mid-1;}
   }
 }
 return -1;
}
 void main()
 {
  int a[15]={3,7,12,19,21,24,26,33,39,41,45,50,52,64,68};
  printf("%d ",find(a,52));
 }