#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B;
  string s;
  bool f = false;
  if (s.at(A) != '-') f = true;
  for (int i = 0; i < s.size(); i++) {
    if (i != A) {
      if (s.at(i) == '-') f = true;
    }
  }
  if (f)
    cout << "No" << endl;
  else
    cout << "Yes" << endl;
}
