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