#include <bits/stdc++.h>
using ll = long long;
using namespace std;
#define rep(i,n) for(int i=0, i##_len=(int)(n); i<i##_len; i++)
#define reps(i,n) for(int i=1 , i##_len=(int)(n);i<=i##_len;i++)
#define rrep(i,n) for(int i=((int)(n)-1);i>=0;i--)
#define rreps(i,n) for(int i=((int)(n));i>0;i--)
#define repi(i,x) for(auto i=(x).begin(),i##_fin=(x).end();i!=i##_fin;i++)
#define all(x) (x).begin(), (x).end()
#define F first
#define S second
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define eb emplace_back
string solve(bool a) { return ((a) ? "Yes" : "No"); }
typedef vector<int> Vi;
typedef vector<Vi> VVi;
typedef pair<int , int> Pi;
typedef vector<Pi> VPi;
typedef vector<long long> V;
typedef vector<V> VV;
typedef pair<long long , long long> P;
typedef vector<P> VP;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1;} return 0;}
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1;} return 0;}
template <class T, class U>ostream& operator<<(ostream& os, const pair<T, U>& p) {
	os << "(" << p.first << "," << p.second << ")";
	return os;
}
template <class T>ostream& operator<<(ostream& os, const vector<T>& v) {
	os << "{";
	rep(i, v.size()) {
		if (i) os << ",";
		os << v[i];
	}
	os << "}";
	return os;
}
template <class T, class U>istream& operator>>(istream& is, pair<T, U>& p) {
	is >> p.first >>p.second ;
	return is;
}
template <class T>istream& operator>>(istream& is,  vector<T>& v) {
	rep(i, v.size()) {
		is >> v[i];
	}
	return is;
}
const long long INFLL = 1LL<<60;
const int INF = 1<<30;
const double PI=acos(-1);
int main(){
	string s;
	int ans=0;
	cin >>s;
	set<char>dis;
	for(char i:s){
		dis.insert(i);
	}
	dis.insert('z' + 6);
	for (char i = 'a'; i <= 'z'; i++) {
		if(*dis.lower_bound(i)!=i){
			cout << i << endl;
			return 0;
		}
	}
	cout << "None" << endl;
}
//list index out of rangeエラー表示用
#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define rep1(i, n) for (int i = 0; i < (int)(n); i++)
#define rep2(i, s, n) for (int i = (s); i < (int)(n); i++)



int main(){
  int n;
  cin >> n;
  vector<int> l(n);
  rep1(i, n){
    cin >> l[i];
  }
  int ans = 0;
  rep2(i, 0, n-2){
    rep2(j, i+1, n-1){
      rep2(k, j+1, n){
        int a = l[i];
        int b = l[j];
        int c = l[k];
        if(a != b && b != c && c != a && a+b > c && b+c > a && c+a > b){
          ans += 1;
          
        }
       
      }
    }
  }
  cout << ans;

}