#include <stdio.h>
#include <stdlib.h>
 
int binary_search(int a[],int n,int x){
    int i=0,j=n-1;
    while (i<=j){
        int m=(i+j)/2;
        if (a[m]==x)return m;
        if (a[m]<x) i=m+1;
        else j=m-1;
    }
    return -1;
}
 
int main(){
    int n,x,*a;
    scanf("%d %d",&n,&x);
    a=malloc(sizeof(int)*n);
    for (int i=0;i<n;i++) scanf("%d",&a[i]);
 
    int 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;
}

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