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