text: /*
  AtCoder Beginner Contest 179 - A - Plural Form Editorial
  https://atcoder.jp/contests/abc179/tasks/abc179_a
  */
  
  #include <bits/stdc++.h>
  using namespace std;
  
  typedef long long ll;
  typedef pair<int, int> pii;
  typedef pair<ll, ll> pll;
  typedef pair<string, string> pss;
  typedef vector<int> vi;
  typedef vector<vi> vvi;
  typedef vector<pii> vii;
  typedef vector<ll> vl;
  typedef vector<vl> vvl;
  
  double EPS=1e-9;
  int INF=1000000005;
  long long INFF=1000000000000000005ll;
  double PI=acos(-1);
  int dirx[8]={ -1, 0, 0, 1, -1, -1, 1, 1 };
  int diry[8]={ 0, 1, -1, 0, -1, 1, -1, 1 };
  const ll MOD = 1000000007;
  
  ll sum() { return 0; }
  template<typename T, typename... Args>
  T sum(T a, Args... args) { return a + sum(args...); }
  
  #define DEBUG fprintf(stderr, "====TESTING====\n")
  #define VALUE(x) cerr << "The value of " << #x << " is " << x << endl
  #define OUT(x) cout << x << endl
  #define OUTH(x) cout << x << " "
  #define debug(...) fprintf(stderr, __VA_ARGS__)
  #define READ(x) for(auto &(z):x) cin >> z;
  #define FOR(a, b, c) for (int(a)=(b); (a) < (c); ++(a))
  #define FORN(a, b, c) for (int(a)=(b); (a) <= (c); ++(a))
  #define FORD(a, b, c) for (int(a)=(b); (a) >= (c); --(a))
  #define FORSQ(a, b, c) for (int(a)=(b); (a) * (a) <= (c); ++(a))
  #define FORC(a, b, c) for (char(a)=(b); (a) <= (c); ++(a))
  #define EACH(a, b) for (auto&(a) : (b))
  #define REP(i, n) FOR(i, 0, n)
  #define REPN(i, n) FORN(i, 1, n)
  #define MAX(a, b) a=max(a, b)
  #define MIN(a, b) a=min(a, b)
  #define SQR(x) ((ll)(x) * (x))
  #define RESET(a, b) memset(a, b, sizeof(a))
  #define fi first
  #define se second
  #define mp make_pair
  #define pb push_back
  #define ALL(v) v.begin(), v.end()
  #define ALLA(arr, sz) arr, arr + sz
  #define SIZE(v) (int)v.size()
  #define SORT(v) sort(ALL(v))
  #define REVERSE(v) reverse(ALL(v))
  #define SORTA(arr, sz) sort(ALLA(arr, sz))
  #define REVERSEA(arr, sz) reverse(ALLA(arr, sz))
  #define PERMUTE next_permutation
  #define TC(t) while (t--)
  #define FAST_INP  ios_base::sync_with_stdio(false);cin.tie(NULL)
  #define what_is(x) cerr << #x << " is " << x << endl;
  
  void solve() {
  	
  }
  
  int main()
  {
      FAST_INP;
  //    #ifndef ONLINE_JUDGE
  //    freopen("input.txt","r", stdin);
  //    freopen("output.txt","w", stdout);
  //    #endif
  
  //    int tc; cin >> tc;
  //    TC(tc) solve();
  	string s;
  	cin >> s;
  	int n = s.size();
  	// check the last characher, add es if it is s, else s
  	if(s[n-1]=='s') s+="es";
  	else s+="s";
  	OUT(s);
      return 0;
  }
  