using System;
 
public class Test
{
	public static void Main()
	{
		String nome = "abbabba";
 
		var i = 0; // começo
		var j = nome.Length-1; // fim
		var tamanho = 0;
		var sufixoEprefixo = "";
 
		while (i <= j) {
			if (nome[i] == nome[j]) {
				tamanho++;
				sufixoEprefixo += nome[i];
			} else {
				break;
			}
			i++;
			j--;
		}
		Console.WriteLine(tamanho);
		Console.WriteLine(sufixoEprefixo);
	}
}
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