#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  string s;
  if (s.size() != a + b + 1) {
    cout << "No" << endl;
    return 0;
  }
  for (int i = 0; i < a; i++) {
    if (s.at(i) == '-') {
      cout << "No" << endl;
      return 0;
    }
  }
  for (int i = a + 1; i < a + b + 1; i++) {
    if (s.at(i) == '-') {
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
}
