using namespace std;

int main() {
  int a, b; cin >> a >> b;
  string s; cin >> s;
  string ans = "Yes";
  
  for (int i = 0; i < s.size(); ++i) {
    char c = s[i];
    if (i == a) {
      if (c != '-') {
        ans = "No";
        break;
      }
    }
    else {
      if (c == '-') {
        ans = "No";
      	break;
      }
    }
  }
  
  cout << ans << endl;
  
  return 0;
}