using System;

using System.Numerics;

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Console.WriteLine(9.ToString("D1"));

Console.WriteLine(new BigInteger(9).ToString("D1"));

​

Console.WriteLine(1.ToString("B1"));

Console.WriteLine(new BigInteger(1).ToString("B1"));

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Console.WriteLine(15.ToString("X1"));

Console.WriteLine(new BigInteger(15).ToString("X1"));