#include <stdio.h>
#include <stdlib.h>

int binary_search(int a[],int n,int x){
	int left = 0;
	int right = n - 1;
	int center;
	
	while(left <= right){
		center = (left + right) / 2;
		
		if(a[center] == x){
			return center;
		}
		else if(a[center] < x){
			left = center + 1;
		}
		else{
			right = center - 1;
		}
	}
	
	return -1;
}

int main(void) {
	int n,x,i;
	int *a;
	int ans = -1;

	scanf("%d %d",&n,&x);

	a = (int*)malloc(sizeof(int)*n);

	if(a==NULL){
		printf("ERROR\n");
		return -1;
	}

	for(i=0;i<n;i++){
		scanf("%d",&a[i]);
	}

	ans = binary_search(a,n,x);

	if(ans != -1){
		printf("a[%d] = %d\n",ans,a[ans]);
	}
	else{
		printf("not found\n");
	}

	free(a);

	return 0;
}