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