#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC target("sse4")
using namespace std;
const double PI = acos(-1.0);
const double EPS = 1e-6;
const int INF = 1000000007;
const long long LINF = 1e18;
const long long mod = 1000000007;
const long long MAX = 100047;
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  string S;
  int a = 0, b = 0;
  cin >> S;
  for (int i = (0); i < ((int)((S).size())); ++i)
    if (S[i] == '-')
      ++a;
    else
      ++b;
  if (b == 0 || a % b == 0)
    cout << "YES";
  else
    cout << "NO";
  return 0;
}
