#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  int cnt = 0;
  for (auto c : s) {
    if (c == '-') {
      cnt++;
    }
  }
  if (cnt == 1) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
  return 0;
}
