gistfile1.java

import java.util.Scanner;
import java.util.Arrays;

public class A {
	
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner in = new Scanner(System.in);
		
		while(in.hasNextLine()){
			int loads = in.nextInt();
			
			if(loads == 0) { break; }
			
			in.nextLine();
			
			String line = in.nextLine();
			
			Scanner tmp = new Scanner(line);
			
			int time = 0;
			
			int[] dryTime = new int[loads];
			
			for(int i=0;i<loads;i++){
				dryTime[i] = tmp.nextInt();
			}
			
			Arrays.sort(dryTime);
			
			for(int i=1;i<loads;i++){
				time += dryTime[i];
			}
			
			if(time < (loads-1) * 30)
				time = (loads-1) *30;
			
			time += 30;
			time += dryTime[0];
			
			System.out.printf("%d:%02d\n", time / 60, time % 60);
		}
	}

}