// 2023 IUSB Programming Competition
// Round 1 Problem 3
// Gold Price
// Solution by Liguo Yu

import java.util.Scanner;

public class round1_p3
{   
    public static void main(String[] args)
    {
        Scanner input = new Scanner(System.in);
        int bYear = input.nextInt();
        int n = input.nextInt(); // number of years
        
        float[] price = new float[n];
        
        for(int i=0; i<n; i++)
        {
            price[i] =input.nextFloat();
        }
        
        double max = (price[1] - price[0]) / price[0];
        int index = 0;
        
        for(int i=1; i<n; i++)
        {
            if((price[i] - price[i-1]) / price[i-1] > max)
            {
                max = (price[i] - price[i-1]) / price[i-1];
                index = i-1;
            }
        }
        int year = bYear + index;
        int next_year = year + 1;
        System.out.println(year + " - " + next_year);
    }
}