using System;
public class Program
{
public static void Main()
int mark,max=0;
for ( int i=0; i<10 ; i++)
Console.WriteLine("enter a mark");
mark=int.Parse(Console.ReadLine());
if ( mark<55)
if (mark>max)
max=mark;
}
if ( max==0)
Console.WriteLine("-1");
else
Console.WriteLine(max);