#include <algorithm>
#include <iostream>
#include <memory.h>
#include <iterator>
#include <cassert>
#include <fstream>
#include <iomanip>
#include <cstdlib>
#include <bitset>
#include <vector>
#include <cstdio>
#include <string>
#include <queue>
#include <deque>
#include <cmath>
#include <ctime>
#include <stack>
#include <set>
#include <map>

using namespace std;

const int N = (int)2e5 + 10;

int n;
long long a[N];

int main ()
{
    //freopen("input.txt" , "r" , stdin);
    //freopen("output.txt" , "w" , stdout);
    ios_base::sync_with_stdio(false);

    cin >> n;
    long long timeD = -1;
    for(int i = 0; i < n; ++i) {
        cin >> a[i];
    }
    timeD = a[1] - a[0];
    for(int i = 1; i < n; ++i) {
        if(timeD != a[i] - a[i - 1]) {
            cout << "kukuha" << endl;
            return 0;
        }
    }

    long double d = timeD * (n - 1) * 1.0;
    cout << (d - 1) / 2.0 << ' ' << (d + 1) / 2.0 << endl;




    return 0;
}