#include <iostream>
#include<queue>

using namespace std;

int main()
{
    int n,meret,eleje=0,vege=0,index;
    cin>>n;
    meret=n;
    int nums[n+1];
    bool volte[n+1];
    priority_queue<pair<int,int> > seged;
    for(int i=1;i<=n;i++)
    {
        cin>>nums[i];
        volte[i]=false;
        seged.push(make_pair(nums[i],i));
    }
    while(!seged.empty())
    {
        index=seged.top().second;
        seged.pop();
        volte[index]=true;
        if(index!=meret && meret-index>=vege-eleje)
        {
            eleje=index;
            vege=meret;
        }
        while(volte[meret])--meret;
    }
    if(eleje==0)
    {
        cout<<-1;
        return 0;
    }
    cout<<eleje<<" "<<vege;
    return 0;
}