public static void Main()
{
string twentySixBasedNumberAsString = Console.ReadLine();
string operationSign = Console.ReadLine();
string sevenBasedNumberAsString = Console.ReadLine();
BigInteger sum = 0;
if (operationSign.Contains("+"))
{
sum = NumberConverter.TwentySixBasedNumberToDecimalNumber(twentySixBasedNumberAsString)
+ NumberConverter.SevenBasedNumberToDecimalNumber(sevenBasedNumberAsString);
}
if (operationSign.Contains("-"))
{
sum = NumberConverter.TwentySixBasedNumberToDecimalNumber(twentySixBasedNumberAsString)
- NumberConverter.SevenBasedNumberToDecimalNumber(sevenBasedNumberAsString);
}
Console.WriteLine(NumberConverter.DecimalNumberToNineBasedNumber(sum));
}