#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define OO 2'000'000'000
#define ull unsigned long long
#define nl '\n'
#define sz(x) (ll)(x.size())
#define all(x) x.begin(),x.end()
#define rall(s)  s.rbegin(), s.rend()
#define getline(s) getline(cin>>ws,s)
#define ceill(n, m) (((n) / (m)) + ((n) % (m) ? 1 : 0))
#define pi  3.141592653589793
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define multi_ordered_set tree<int, null_type,less_equal<int>, rb_tree_tag,tree_order_statistics_node_update>


void Fast_IO(){
ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
// freopen("filename.in", "r", stdin);
// freopen("filename.txt", "w", stdout);
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
#endif
}




int dx[] = { 2, 1, -1, -2, -2, -1, 1, 2 };
int dy[] = { 1, 2, 2, 1, -1, -2, -2, -1 };




void solve(){
  ll n; cin>>n;
  vector<ll>v(n);
    for(int i=0;i<n;i++)cin>>v[i];
    vector<ll>part(n+1);
    for(int i=0;i<n;i++){
        part[i]+=1;
        ll x = min(n,i+v[i]);
        part[x]-=1;
    }

    for(int i=1;i<n;i++){
        part[i]+=part[i-1];
    }

    ll mx = -1,cnt = 0,pos = -1;
    for(ll i=0;i<n;i++){
        if(part[i]==1){
            cnt++;
        }
        else{
            if(cnt > mx and cnt){
                mx = cnt;
                pos = i-cnt+1;
            }
            cnt = 0;
        }
    }

    if(cnt > mx and cnt){
        mx = cnt;
        pos = n-cnt+1;
    }


    if(pos == -1){
        cout<<-1<<nl;
    }
    else{
        cout<<mx<<" "<<pos<<nl;
    }



}

int main(){
    Fast_IO();
int t =1;
//cin>>t;
while(t--){
solve();
}
return 0;
}