# include <algorithm> # include <iostream> using namespace std; int main(){ int n,m; cin >> n; int a[n]; for (int i = 0;i < n;i++) cin >> a[i]; sort(a,a+n); cin >> m; int l = 0,r = n - 1; while (l < r){ int mid = l + r >> 1; if (a[mid] == m){ cout << mid + 1; return 0; }else if (a[mid] > m){ r = mid - 1; }else{ l = mid + 1; } }cout << -1; return 0; }