import std.algorithm, std.conv, std.range, std.stdio, std.string;
import std.regex;     // RegEx

void main()
{
  auto s = readln.chomp;
  auto m = s.matchAll(r"c[^w]*?w[^w]*?w");
  auto r = 0;
  foreach (mi; m)
    r = max(r, mi[0].length.to!int);
  writeln(r == 0 ? -1 : r);
}