#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, cnt = 0;
  string s;
  cin >> a >> b >> s;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] == '-') cnt++;
    if (cnt >= 2) {
      cout << "No";
      return 0;
    }
  }
  if (s[a] == '-' && 0 <= s.size() && s.size() <= 9)
    cout << "Yes";
  else
    cout << "No";
}
