import std.stdio;
import std.algorithm;
import std.range;
import std.regex;
import std.exception;

void main()
{
    auto line = readln;
    iota(0, line.length)
        .map!(i => line[i..$])
        .map!(x => x.matchFirst(ctRegex!"c[^w]*?w[^w]*?w")[0].length)
        .fold!"b > 0 && a > b ? b : a".ifThrown(-1)
        .writeln;
}