#include<iostream>
#include<map>
#include<vector>
#include<deque>
#include<string>
#define int long long
using namespace std;
map<deque<int>,bool>mp;
int n;
string s;
signed main(){
	cin>>n;
	cin>>s;
	int i=0,j=0;
	int cnt=0;
	deque<int>nows;
	nows.push_back(s[0]);
	while(j<n){
		while(j<n and s[j]==s[i]){
			if(!mp[nows]){
				cnt++;
				mp[nows]=true;
			}
			j++;
			nows.push_back(s[j]);
		}
		j--;
		nows.pop_back();
		while(i<=j){
			nows.pop_front();
			i++;
		}
		j=i;
	}
	cout<<cnt<<endl;
	return 0;
}

用例:

6
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