#include<bits/stdc++.h> using namespace std; int main(){ int n; cin>>n; int a[n]; for(int i=0;i<=n-1;i++){ cin>>a[i]; } int x; cin>>x; int y=-1; for(int i=0;i<=n-1;i++){ if(a[i]==x){ if(y==-1){ cout<<i+1<<" "; } y=i; } } if(y==-1){ cout<<y; }else{ cout<<y+1; } return 0; }