#include<stdio.h>
void fun(int *a,int n,int S){
int i = n-2, j = n-1;
while (j > 0){
if (a[j] - a[i] < S) i--;
else if (a[j] - a[i] == S) break;
else j--;
}
if (j != 0) printf("yes\n") ;
else printf ("no\n");
}
int main()
{ int arr[]={2,3,7,9};
fun(arr,4,3);
fun(arr,4,5);
fun(arr,4,8);
fun(arr,4,6);
}