#include <iostream>
#include <map>

int main() {
	std::ios::sync_with_stdio(false);
	std::cin.tie(0);

	char c;
	std::map<int, char> pos;
	int minLen = 255;
	
	for (int i = 0; std::cin >> c; ++i) {
		switch (c) {
		case 'c':
		case 'w':
			pos.insert(std::make_pair(i, c));
			break;
		}
	}
	for (std::map<int, char>::iterator it = pos.begin(); it != pos.end(); ++it) {
	FIND_C:
		if (it->second == 'c') {
			for (std::map<int, char>::iterator it2 = it; it2 != pos.end(); ) {
				++it2;
				if (it2->second == 'w') {
					for (std::map<int, char>::iterator it3 = it2; it3 != pos.end(); ) {
						++it3;
						if (it3->second == 'w') {
							minLen = (minLen > it3->first - it->first + 1) ? it3->first - it->first + 1 : minLen;
							++it;
							goto FIND_C;
						}
					}
				}
			}
		}
	}

	std::cout << ((minLen == 255) ? -1 : minLen) << "\n";

	return 0;
}