#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  if (s.size() != (a + b + 1)) {
    cout << "No" << endl;
    return 0;
  }
  bool flag = false;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] != '-' && s[a] == '-') {
      flag = true;
    }
  }
  cout << (flag ? "Yes" : "No") << endl;
  return 0;
}
