#include <bits/stdc++.h>
using namespace std;

string s;

int main() {
   cin >> s;
   int link = 0,perl = 0;
   for(int i = 0; i < s.length(); i++) {
      if(s[i] == '-')
         link++;
      else
         perl++;
   }
   if(perl == 0) {
      puts("YES");
      return 0;
   }
   puts(link % perl == 0 ? "YES" : "NO");
}