#define _USE_MATH_DEFINES	//M_PI(π),M_SQRT2(√2)
#include <iostream>			//std::cout, std::cin
#include <string>			//std::string,std::to_string(C++11)
#include <vector>			//std::vector
#include <valarray>			//std::valarray
#include <algorithm>		//std::sort
#include <time.h>			//localtime_s
#include <cstdlib>			//abs
#include <cmath>			//abs,std::pow,sqrt,sin,cos,round,floor,ceil
#include <fstream>			//std::ifstream,std::ofstream
#include <iomanip>			//std::setprecision,std::setw,std::setfill
#include <random>			//std::random(C++11)
#include <numeric>			//std::accumulate
#include <functional>		//std::greater

int main(void) {

	//test用
	//std::ifstream in("test.txt");
	//std::cin.rdbuf(in.rdbuf());

	//const unsigned int MODULO = 1000000007;	//MODULO 10^9+7用

	std::string S;
	std::cin >> S;

	unsigned int c = 0, w2 = 0, st = -1;
	int ans = -1;

	while (1) {
		unsigned int temp = 0;
		st = S.find("c", st + 1);
		if (st > S.length()) {
			break;
		}
		if (S.find("w", st) <= S.length()) {
			w2 = S.find("w", S.find("w", st) + 1);
			if (w2 <= S.length()) {
				temp = w2 - st + 1;
				if (ans == -1) {
					ans = temp;
				}
				else {
					if (temp <= ans) {
						ans = temp;
					}
				}
			}
		}
		
	}

	std::cout << ans << std::endl;

}