#include <bits/stdc++.h>

const int maxn = 2e5 + 5;
int n,cnt,lst;
char s[maxn];

int main() {
	freopen("photoshoot_bronze_22open.in","r",stdin);
	freopen("photoshoot_bronze_22open.out","w",stdout);
	scanf("%d %s",&n,s + 1);
	for(int i = 1;i <= n;i += 2) {
		if(s[i] == 'G'&&s[i + 1] == 'G') {
			continue ;
		}
		if(s[i] == 'G') {
			if(!cnt) {
				++ cnt;
				lst = 1;
				continue ;
			}
			if(!lst) {
				++ cnt;
				lst = 1;
			}
		}
		if(s[i + 1] == 'G') {
			if(!cnt) {
				++ cnt;
				lst = 0;
				continue ;
			}
			if(lst) {
				++ cnt;
				lst = 0;
			}
		}
	}
	
	printf("%d\n",cnt - (lst ^ 1));
	return 0;
}