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

int binary_search(int a[], int n, int x){

    int lef = 0;
    int rig = n - 1;
    int mid;

    while(lef <= rig){

        mid = (lef + rig) / 2;

        if(a[mid] == x){
            return mid;
        }
        else if(x < a[mid]){
            rig = mid - 1;
        }
        else{
            lef = mid + 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);

    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;
}