#include <iostream>
#include <algorithm>

using namespace std;

int main(){
    int n = 0;
    cout << "Size : ";
    cin >> n;
    int a[n] = {};
    cout << "Elements : ";
    for (int i = 0; i < n; ++i) cin >> a[i];
    int key = 0;
    cout << "Key : ";
    cin >> key;

    sort(a, a + n);

    int l = -1;
    int r = n;
    while (l < r - 1){
        int m = (l + r) / 2;
        if (key > a[m]) l = m;
        else r = m;
    }

    if (a[r] == key) cout << "First element's index in sorted array : " << r;
    else cout << "Array doesn't have such element";
    return 0;
}