#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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