#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int N = 1e3 + 100;
ll n;
char c[N]; 

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	
	cin >> n;
	
	for (int i = 1;i <= n;i++){
		cin >> c[i];
	}
	
	char now = c[1];//记录当前字符 
	ll cnt = 1;//记录当前字符的数量 
	
	for (int i = 2;i <= n;i++){
		if (now == c[i]){	
			cnt++;//字符的数量++ 
		}else {
			//不重复之后进行输出 上段重复的内容 (数量 + 字符)
			
			cout << cnt << now; //不用换行 
			
			cnt = 1;//若不重复则清空数组 
			now = c[i];//并标记这个字符 
		}
	}
	
	cout << cnt << now; 

	return 0;
}