#include <bits/stdc++.h>
using namespace std;
signed main() {
  long long a, b;
  string s, l;
  cin >> a >> b;
  cin >> s;
  for (long long j = 0; j < a; j++) {
    for (long long k = a + 1; k < b; k++) {
      if (s[a] == '-' && s[j] != '-' && s[k] != '-')
        l = "Yes";
      else
        l = "No";
    }
  }
  cout << l << endl;
  getchar();
  getchar();
  return 0;
}
