#include<bits/stdc++.h>
using namespace std;
const int N=2e6+7;
int n;
char st[N];
stack<char> sta;
int ans;
signed main(){
	freopen("game.in","r",stdin);
	freopen("game.out","w",stdout);
	scanf("%d",&n);
	scanf("%s",&st);
	for(int i=0;i<n;++i){
		for(int j=i;j<n;++j){
			if(!sta.empty()&&sta.top()==st[j]){
				sta.pop();
				if(sta.empty()) ++ans;
				continue;
			}
			sta.push(st[j]);
		}
		while(!sta.empty()) sta.pop();
	}
	printf("%d\n",ans);
	return 0;
}

交洛谷没死,云斗自测也没 官方评测会寄吗