// yukicoder 345 (http://yukicoder.me/problems/984)
#include<iostream>
#include<string>
#define rep(i,a) for(int i=0;i<(a);++i)

const std::string cww = "cww";

std::string S;

int main()
{
	std::cin >> S;

	int cnt = 0, s;
	rep( i, S.size() )
	{
		if( S[i] == cww[cnt] )
		{
			if( !cnt )
				s = i;

			++cnt;
		}

		if( cnt == 3 )
		{ printf( "%d\n", i-s+1 ); return 0; }
	}

	puts("-1");

	return 0;
}