using System;
class Program
{
static void Main()
int num = 10;
bool found = false;
while (found == false && num <= 99)
int tens = num / 10;
int units = num % 10;
if (tens + units == 7 && tens - units == 3)
found = true;
else
num++;
}
Console.WriteLine(num);
num = 99;
found = false;
while (found == false && num >= 10)
num--;