PROBLEM 266A CODEFORCES

/* Problem from : https://codeforces.com/problemset/problem/266/A */

/* code dạo là đam mê :v */
#include <iostream>
#include <string>

using namespace std;

int main()
{
    int n;
    cin >> n;
    string s;
    cin >> s;
    int r = 0;
    int g = 0;
    int b = 0;
    for (int i = 1; i < n; i++)
    {
        if (s[i - 1] == s[i])
        {
            if (s[i] == 'R')
            {
                 ++r;
            }
            else
            {
                if(s[i]=='G')
                {
                    ++g;
                }
            }
        }
        else
        {
            if(s[i]=='B')
                ++b;
        }
    }
    cout << r + g + b;
    return 0;
}