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