#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B;
  cin >> A >> B;
  string str;
  cin >> str;
  int s = 0;
  bool result = true;
  for (char a : str) {
    if (s < A && '-' == a) {
      result = false;
    }
    if (s == A && '-' != a) {
      result = false;
    }
    s++;
  }
  cout << (result ? "Yes" : "No") << endl;
  return 0;
}
