using System;

public class Program {
	public void Solve() {
		char[] c = Console.ReadLine().ToCharArray();
		int min = c.Length + 1;
		for (int i = 0; i < c.Length; i++) {
			int count = 0;
			int w = 0;
			if (c[i].Equals('c')) {
				count++;
				for (int j = i + 1; j < c.Length; j++) {
					count++;
					if (c[j].Equals('c') && w == 0) {
						i = j - 1;
						break;
					} else if (c[j].Equals('w')) {
						w++;
						if (w == 2 && count < min) {
							min = count;
							break;
						}
					}
				}
			}
		}
		if (min == c.Length + 1) {
			Console.WriteLine(-1);
		} else {
			Console.WriteLine(min);
		}
	}
	
	public static void Main(string[] args) {
		Program program = new Program();
		program.Solve();
	}
}