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