#include <bits/stdc++.h>
using namespace std;
const int mill = 1e9;
const long long mln = 1e6;
const int INF = 2e9;
const long long mod = 1e9 + 7;
const long long mod2 = 3e9 - 71;
const long long longINF = 3e18;
const long double pi = acos(-1);
const long double eps = 1e-8;
const int M = 1 << 21;
const long long smod = 998244353;
string s;
int k, res;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  srand(time(0));
  cin >> s;
  k = (int)s.length();
  for (int i = 0; i < k; i++) {
    if (s[i] == 'o') res++;
  }
  cout << (res != 0 && (k - res) % res ? "NO" : "YES");
  return 0;
}
