#include using namespace std; //#include //using namespace atcoder; using ll = long long; using vll = vector; using vvll = vector; using vvvll = vector; using vvvvll = vector; using vvvvvll = vector; using vvvvvvll = vector; using vb = vector; using vvb = vector; using vvvb = vector; using vvvvb = vector; using vd = vector; using vvd = vector; using vvvd = vector; using vvvvd = vector; using vvvvvd = vector; #define all(A) A.begin(),A.end() #define ALL(A) A.begin(),A.end() #define rep(i, n) for (ll i = 0; i < (ll) (n); i++) using pqr = priority_queue, vector>, greater>>; template bool chmax(T& p, T q, bool C = 1) { if (C == 0 && p == q) { return 1; } if (p < q) { p = q; return 1; } else { return 0; } } template bool chmin(T& p, T q, bool C = 1) { if (C == 0 && p == q) { return 1; } if (p > q) { p = q; return 1; } else { return 0; } } ll gcd(ll(a), ll(b)) { if (a == 0)return b; if (b == 0)return a; ll c = a; while (a % b != 0) { c = a % b; a = b; b = c; } return b; } ll sqrtz(ll N) { ll L = 0; ll R = sqrt(N) + 10000; while (abs(R - L) > 1) { ll mid = (R + L) / 2; if (mid * mid <= N)L = mid; else R = mid; } return L; } /* using mint = modint998244353; //using Mint = modint; vector fact, factinv, inv; const ll mod = 998244353; void prenCkModp(ll n) { fact.resize(n + 5); factinv.resize(n + 5); inv.resize(n + 5); fact[0] = fact[1] = 1; factinv[0] = factinv[1] = 1; inv[1] = 1; for (ll i = 2; i < n + 5; i++) { fact[i] = (fact[i - 1] * i); inv[i] = mod - (inv[mod % i] * (mod / i)); factinv[i] = (factinv[i - 1] * inv[i]); } } mint nCk(ll n, ll k) { if (n < k || k < 0) return 0; return fact[n] * (factinv[k] * factinv[n - k]); } */ template vector> mul(vector> A, vector> B) { ll N = A.size(); vector> res(N, vector(N, 0)); rep(i, N)rep(j, N)rep(k, N) { res[i][j] += A[i][k] * B[k][j]; } return res; } vll S(vll V,ll A){ A--; vll res; res.push_back(V[A]); rep(i,V.size()){ if(i!=A)res.push_back(V[i]); } return res; } int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); string S; cin>>S; set C; for(auto c:S)C.insert(c); cout<<(C.size()==S.size()?"YES":"NO")<