#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  string s;
  cin >> a >> b;
  bool ok = true;
  if (s[a] == '-') {
    for (int i = 0; i < s.size(); i++) {
      if (i != a) {
        if (s[a] == '0' || s[a] == '1' || s[a] == '2' || s[a] == '3' ||
            s[a] == '4' || s[a] == '5' || s[a] == '6' || s[a] == '7' ||
            s[a] == '8' || s[a] == '9') {
        } else {
          ok = false;
        }
      }
    }
  } else {
    ok = false;
  }
  if (ok) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
  return 0;
}
