#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;
  else {
    if (s[a] == '-')
      cout << "Yes" << endl;
    else
      cout << "No" << endl;
  }
  return 0;
}
