#include <iostream>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <string>
#include <map>
#include <vector>
#include <queue>
#include <stack>
#include <deque>

using namespace std;

#define rd read()
#define int long long


// const int N = ;
const int MOD = 998244353;
const int INF = 0x7fffffff;
const int Fill = 0x3f;
const int FillINF = 0x3f3f3f3f;

void write(int n)
{
    if (n < 0)
    {
        putchar('-');
        n = -n;
    }
    if (n < 10)
    {
        putchar(n + '0');
        return;
    }
    write(n / 10);
    putchar(n % 10 + '0');
    return;
}
void wt(int n, bool o = 1)
{
    write(n);
    if (!o)
    {
        putchar(' ');
    }
    else
    {
        putchar('\n');
    }
}

int read()
{
    char ch;
    int type = 1, n = 0;
    ch = getchar();
    while (ch < '0' || ch > '9')
    {
        if (ch == '-')
        {
            type = -1;
        }
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9')
    {
        n = (n << 1) + (n << 3) + (ch ^ 48);
        ch = getchar();
    }
    return n * type;
}

int n;

void solve()
{
    int i, j;
    int cnt = 0;
    string s, ans = "";
    char now;
    n = rd;
    cin >> s;
    now = s[0];
    cnt = 1;
    if (n == 1)
    {
        cout << 1 << s;
        return ;
    }
    for (i = 1; i < s.size(); i++)
    {
        if (s[i] == now)
        {
            cnt++;
            continue;
        }
        cout << cnt << now;
        cnt = 1;
        now = s[i];
    }
    cout << cnt << now;
}

signed main()
{
    int T;
    int i, j;
    T = 1;
    while (T--)
    {
        
        solve();
    }
    return 0;
}