import java. util.*;
public class Main{
public static void main(String[] args){
Scanner in = new Scanner(System.in);
int n = in.nextInt();
int[] number = new int[n];
for(int i = 0 ;i<n;i++){
number[i] = in.nextInt();
}
if(n<3)
System.out.println(-1+" "+-1);
else{
//思路是求出所有可能的断点,即左边为下降,右边为上升的转折点,然后枚举相邻两点的距离
//最长的即为所求。
List<Integer> breakpoint = new ArrayList<Integer>();
if(number[1]>number[0])
breakpoint.add(0);
for(int i = 1 ; i<n-1 ; i++){
if(number[i]<number[i-1]&&number[i]<number[i+1])
if(!breakpoint.contains(i))
breakpoint.add(i);
}
if(number[n-1]<number[n-2]){
if(!breakpoint.contains(n-1))
breakpoint.add(n-1);
}
int length = Integer.MIN_VALUE;
int start = 0 , end = 0;
if(breakpoint.size()>1){
for(int i = 1 ; i<breakpoint.size(); i++){
if(breakpoint.get(i)-breakpoint.get(i-1)>length){
length = breakpoint.get(i)-breakpoint.get(i-1);
start = breakpoint.get(i-1);
end = breakpoint.get(i);
}
}
System.out.println(start+" "+end);
}else{
System.out.println(-1+" "+-1);
}
}
}
}