#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using PII = std::pair<int, int>;
using PLL = std::pair<ll, ll>;

#define rep(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()
{

#ifdef DEBUG
    cout << "DEBUG MODE" << endl;
    ifstream in("input.txt"); //for debug
    cin.rdbuf(in.rdbuf());    //for debug
#endif

    int w[26];
    string s, ans;
    cin >> s;
    for (auto z : s)
        w[z - 'A']++;
    
    ans = "NO";
    if (s.length() <= 10 && *max_element(w, w+26) == 1)
        ans = "YES";
    cout << ans << endl;

    return 0;
}