AC-174C.cpp

//This code is written by Shammi Anand
#include<bits/stdc++.h>
using namespace std;

#define ll              long long
#define Max(a,b,c)      max(a,max(b,c))
#define Min(a,b,c)      min(a,min(b,c))
#define pb              push_back
#define mp              make_pair
#define f               first
#define s               second
#define mod             1000000007
#define nl              "\n"
#define w(x)            int x; cin>>x; while(x--)

void shammi() {
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#ifndef ONLINE_JUDGE
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#endif
}
int main() {
	shammi();
	int N; cin >> N;
	string C; cin >> C;
	int c = 0;
	for (int i = 0; i < N - 1; i++) {
		if (C[i] == 'W' && C[i + 1] == 'R') c++;
	}

	cout << c << nl;

	return 0;

}