#include <bits/stdc++.h>
using namespace std;

int main()
{
    string s;
    cin >> s;

    int odp = 0;
    int siz = s.size();

    for (int i = 1; i < siz; ++i)
    {
        if (s[i] == s[i - 1])
        {
            ++odp;
        }
    }

    cout << odp;
    return 0;
}