#include <bits/stdc++.h>
using namespace std;
int main() {
  int pre, post;
  string input;
  cin >> pre >> post;
  cin >> input;
  int len = pre + post + 1;
  int mid = input.find("-");
  if (mid == string::npos) {
    cout << "No" << endl;
    return 0;
  }
  string result =
      ((pre == mid - 1) && (post == (input.size() - mid))) ? "Yes" : "No";
  cout << result << endl;
}
