#include <iostream>
using namespace std;
int main() {
// your code goes here
int count=0;
int t;
cin>>t;
string s;
cin>>s;
for(int i=0;i<t;i++)
{
if(s[i]==s[i+1])
{
count++;
}
}
cout<<count<<endl;
return 0;
}
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