using System;

public class Program
{
	public static void Main()
	{
		var S = Console.ReadLine();
		int min = int.MaxValue;
		for (int i = 0; i < S.Length - 2; i++)
		{
			if (S[i] == 'c')
			{
				int w = 0;
				for (int j = i + 1; j < S.Length; j++)
				{
					if (S[j] == 'w')
					{
						if (++w == 2)
						{
							min = Math.Min(min, j - i + 1);
							break;
						}
					}
				}
			}
		}
		Console.WriteLine(min < int.MaxValue ? min : -1);
	}
}