#include <bits/stdc++.h>
using namespace std;
using ll = long long;
//#include <atcoder/modint>
//using namespace atcoder;
//using mint = modint998244353;
# define M_PI           3.14159265358979323846  /* pi */
#define watch(x) cout << (#x) << " is " << (x) << endl
 
//#pragma GCC target ("avx2")
#pragma GCC optimization ("Ofast")
 
#if 0
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template <class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template <class K, class V> using ordered_map = tree<K, V, less<K>, rb_tree_tag, tree_order_statistics_node_update>;
#endif

const int MOD = (1e9+7);
template < typename T = int > ostream& operator << (ostream &out, const vector < T > &v){ 
    for (const T &x: v) out << x << ' '; 
    return out;
}
template<class T>
void printmat(const vector<vector<T>>& mat) {
    for (auto row : mat) {
        for (auto elem : row)
            cout << elem << " ";
        cout << "\n";
    }
}
void printdq(const deque<int>& v) {
    for (auto elem : v)
        cout << elem << " ";
    cout << endl;
}
template<class T>
void printv(const vector<T>& v) {
    for (auto elem : v)
        cout << elem << " ";
    cout << "\n";
}
template<class T>
void printdq(const deque<T>& v) {
    for (auto elem : v)
        cout << elem << " ";
    cout << endl;
}
template<class T1, class T2>
void printvp(const vector<pair<T1,T2>>& vp) {
    for (auto pr : vp) {
        cout << pr.first << " " << pr.second;
        cout << "\n";
    }
}
void printvs(const vector<set<int>>& vs) {
    for (auto row : vs) {
        for (auto elem : row)
            cout << elem << ", ";
        cout << endl;
    }
}
template<class T>
void printht(const unordered_map<T, T>& ht) {
    for (auto elem : ht)
        cout << elem.first << " : " << elem.second << endl;
}
template<class T1, class T2>
void printmp(const map<T1, T2>& ht) {
    for (auto elem : ht)
        cout << elem.first << " : " << elem.second << endl;
}
template<class T>
void printst(const set<T>& st) {
    for (auto elem : st)
        cout << elem << " ";
    cout << endl;
}
template<class T>
void printms(const multiset<T>& st) {
    for (auto elem : st)
        cout << elem << " ";
    cout << endl;
}
 
bool isPrime(long long n) {
    if (n <= 1)
        return false;
    if (n <= 3)
        return true;
    if (n % 2 == 0 || n % 3 == 0)
        return false;
    for (long long i = 5; i * i <= n; i = i + 6)
        if (n % i == 0 || n % (i + 2) == 0)
            return false;
    return true;
}
 
map<long long, long long> primeFactors(long long n) {
    map<long long, long long> ans;
    while (n % 2 == 0) {
        ans[2]++;
        n = n/2;
    }
    for (long long i = 3; i*i <= (n); i = i + 2) {
        while (n % i == 0) {
            ans[i]++;
            n = n/i;
        }
    }
    if (n > 2)
        ans[n]++;
    return ans;
}
 
/*
    vector<int> uf(n), sz(n,1);
    for (int i=0; i<n; i++) 
        uf[i] = i;
*/
int find_f(const vector<int>& uf, int i) {
    while (uf[i]!=i)
        i = uf[i];
    return i;
}
bool union_f(vector<int>& uf, vector<int>& sz, int a, int b) {
    a = find_f(uf, a);
    b = find_f(uf, b);
    //cout << "a, b = " << a << ", " << b << endl;
    if (a==b) return false;
    if (sz[a] < sz[b]) {
        //cout << "sz[a], sz[b] = " << sz[a] << ", " << sz[b] << endl;
        //cout << "a, b = " << a << ", " << b << endl;
        swap(a,b);
        //cout << "a, b = " << a << ", " << b << endl;
    }
    sz[a] += sz[b];
    uf[b] = a;
    return true;
}
 
long long modexp(long long b, long long e, long long M) {
    if (!e) return 1;
    b %= M;
    long long x = modexp(b * b % M, e / 2, M);
    if (e % 2) {
        return b * x % M;
    } else {
        return x;
    }
}


ll gcdExtended(ll a, ll b, ll* x, ll* y) {
    if (a == 0) {
        *x = 0, *y = 1;
        return b;
    }
    ll x1, y1;
    ll gcd = gcdExtended(b % a, a, &x1, &y1);
    *x = y1 - (b / a) * x1;
    *y = x1;
    return gcd;
}

ll modInverse(ll a, ll m) {
    ll x, y, res=-1;
    ll g = gcdExtended(a, m, &x, &y);
    if (g != 1) {
        //cout << "Inverse doesn't exist";
        res = -1;
    } else {
        // m is added to handle negative x
        res = (x % m + m) % m;
    }
    return res;
}

int lenOfLIS(vector<int>& v) {        
    int n = v.size(), len = 0;
    vector<int> dp(n,0);
    for (int num : v) {
        int i = lower_bound(dp.begin(), dp.begin()+len, num) - dp.begin();
        dp[i] = num;
        if (i == len) {
            len++;
        }
    }
    return len;        
}


#if 0
const int N = 1e6+4;  // limit for array size
int n;  // array size
int t[2 * N];

void build() {  // build the tree
  for (int i = n - 1; i > 0; --i) t[i] = max(t[i<<1], t[i<<1|1]);
}

void modify(int p, int value) {  // set value at position p
  for (t[p += n] = value; p > 1; p >>= 1) t[p>>1] = t[p] + t[p^1];
}

int query(int l, int r) {  // max on interval [l, r)
  int res = 0;
  for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
    if (l&1) res = max(res, t[l++]);
    if (r&1) res = max(res, t[--r]);
  }
  return res;
}
#endif

vector<int> SieveOfEratosthenes(int n) {
    bool prime[n+1];
    memset(prime, true, sizeof(prime));
  
    for (int p=2; p*p<=n; p++) {
        if (prime[p]) {
            for (int i=p*p; i<=n; i+=p)
                prime[i] = false;
        }
    }
    vector<int> v;
    for (int p=2; p<=n; p++)
        if (prime[p])
            v.push_back(p);
    return v;
}

vector<vector<ll>> merge(vector<vector<ll>>& intervals) {
    vector<vector<ll>> ans;
    sort(intervals.begin(), intervals.end());
    vector<ll> curr = intervals[0];
    for (int i=1; i<intervals.size(); i++) {
        if (curr[1]<intervals[i][0]) {
            ans.push_back(curr);
            curr = intervals[i];
        } else {
            curr[1] = max(curr[1], intervals[i][1]);
        }
    }
    ans.push_back(curr);
    return ans;
}



int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);    
    int T=1, caseIdx=0;   
    //cin >> T;    
    while (T--) {
        //caseIdx++;
        //const int M = 998244353;
        int n;
        string s, ans;
        cin >> n >> s;
        vector<int> cnt(26);
        for (char c : s)
            cnt[c-'A']++;
        for (int elem : cnt) {
            ans += to_string(elem);
        }
        
        //cout << fixed << setprecision(9);
        cout << ans << "\n";
        //cout << "Case #" << caseIdx << ": " << ans << "\n";   
    }
}