#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;
}
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