#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  string s;
  scanf("%d%d", &a, &b);
  cin >> s;
  for (int i = 0; i < s.length(); i++) {
    if (s[i] == '-') {
      s.erase(i, 1);
    }
  }
  if (s.length() == a + b)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
