#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base ::sync_with_stdio(false);
  cin.tie(NULL);
  ;
  int a, b;
  cin >> a >> b;
  string str;
  cin >> str;
  bool flag = false;
  for (int i = 0; i < str.size(); i++) {
    if (str[i] == '-' && flag == true) {
      cout << "No";
      return 0;
    } else if (str[i] == '-')
      flag = true;
    else if (str[i] > '9' || str[i] < '0') {
      cout << "No";
      return 0;
    }
  }
  if (flag) {
    cout << "Yes";
  } else
    cout << "No";
  return 0;
}
