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