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