#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  if (s.size() != a + b + 1) {
    cout << "No" << endl;
    return 0;
  }
  if (s.at(a) == '-') {
    for (int i = a + 1; i < s.size(); i++) {
      if (!('0' <= s.at(i) && s.at(i) <= '9')) {
        cout << "No" << endl;
        return 0;
      }
    }
  } else {
    cout << "No" << endl;
    return 0;
  }
  cout << "Yes" << endl;
}
