# include<iostream> using namespace std; int main(){ int n,a[114514],k,i; bool b=0; scanf("%d",&n); for(int i=0;i<n;i++){ scanf("%d",&a[i]); }cin>>k; for(int i=0;i<n;i++){ if(a[i]==k){ cout<<i+1<<" "; b=1; break; } }if(b==0){ cout<<-1; return 0; } for(int i=n-1;i>-1;i--){ if(a[i]==k){ cout<<i+1; break; } } return 0; }