266A.cpp

//266A
#include<iostream>
#include<cstring>
using namespace std;
int main(){
	int n;
	string s;
	cin>>n;
	cin>>s;
	char a;
	int count=0;
	a=s[0];
	for(int i=1;i<s.length();i++){
		if(a==s[i]){
			count++;
		}
		else a=s[i];
	}
	cout<<count;
	return 0;
}