using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using SB = System.Text.StringBuilder;
//using System.Threading.Tasks;
//using System.Text.RegularExpressions;
//using System.Globalization;
//using System.Diagnostics;
using static System.Console;
using System.Numerics;
using static System.Math;
using pair = Pair<int, int>;
class Program
{
static void Main()
{
//SetOut(new StreamWriter(OpenStandardOutput()) { AutoFlush = false });
new Program().solve();
Out.Flush();
}
readonly Scanner cin = new Scanner();
readonly int[] dd = { 0, 1, 0, -1, 0 }; //→↓←↑
readonly int mod = 1000000007;
readonly int dom = 998244353;
bool chmax<T>(ref T a, T b) where T : IComparable<T> { if (a.CompareTo(b) < 0) { a = b; return true; } return false; }
bool chmin<T>(ref T a, T b) where T : IComparable<T> { if (b.CompareTo(a) < 0) { a = b; return true; } return false; }
void solve()
{
var S = ReadLine();
int zero = 0;
int one = 0;
int ans = 0;
for (int i = 0; i < S.Length; i++)
{
if (S[i] == 'w')
{
if (i == S.Length - 1 || S[i + 1] == 'w')
{
ans += Min(one / 2, zero);
one = 0;
zero = 0;
}
else if (one > 0)
{
zero++;
}
}
else
{
one++;
}
}
ans += Min(one / 2, zero);
WriteLine(ans);
}
}
static class Ex
{
public static void join<T>(this IEnumerable<T> values, string sep = " ") => WriteLine(string.Join(sep, values));
public static string concat<T>(this IEnumerable<T> values) => string.Concat(values);
public static string reverse(this string s) { var t = s.ToCharArray(); Array.Reverse(t); return t.concat(); }
public static int lower_bound<T>(this IList<T> arr, T val) where T : IComparable<T>
{
int low = 0, high = arr.Count;
int mid;
while (low < high)
{
mid = ((high - low) >> 1) + low;
if (arr[mid].CompareTo(val) < 0) low = mid + 1;
else high = mid;
}
return low;
}
public static int upper_bound<T>(this IList<T> arr, T val) where T : IComparable<T>
{
int low = 0, high = arr.Count;
int mid;
while (low < high)
{
mid = ((high - low) >> 1) + low;
if (arr[mid].CompareTo(val) <= 0) low = mid + 1;
else high = mid;
}
return low;
}
}
class Pair<T, U> : IComparable<Pair<T, U>> where T : IComparable<T> where U : IComparable<U>
{
public T f; public U s;
public Pair(T f, U s) { this.f = f; this.s = s; }
public int CompareTo(Pair<T, U> a) => f.CompareTo(a.f) != 0 ? f.CompareTo(a.f) : s.CompareTo(a.s);
public override string ToString() => $"{f} {s}";
}
class Scanner
{
string[] s; int i;
readonly char[] cs = new char[] { ' ' };
public Scanner() { s = new string[0]; i = 0; }
public string[] scan => ReadLine().Split();
public int[] scanint => Array.ConvertAll(scan, int.Parse);
public long[] scanlong => Array.ConvertAll(scan, long.Parse);
public double[] scandouble => Array.ConvertAll(scan, double.Parse);
public string next
{
get
{
if (i < s.Length) return s[i++];
string st = ReadLine();
while (st == "") st = ReadLine();
s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
i = 0;
return next;
}
}
public int nextint => int.Parse(next);
public long nextlong => long.Parse(next);
public double nextdouble => double.Parse(next);
}