Pascal :

var a:array[0..100] of longint;
   m,n,i,s:longint;

begin
 readln(m);
 for i:=1 to m do read(a[i]);
 readln;
 read(n);
 s:=-1;
 for i:=1 to m do if a[i]=n then
   begin
    s:=i;
    break;
   end;
 writeln(s);
end.