#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  if (s[a] == '-') {
    if (a <= 5 && b <= 5) {
      for (int i = 0; i < a; i++) {
        if (s[i] - '0' < 0 || s[i] - '0' > 10) {
          cout << "No" << endl;
          return 0;
        }
        cout << "Yes" << endl;
        return 0;
      }
    }
    cout << "No" << endl;
    return 0;
  }
  cout << "No" << endl;
  return 0;
}
