#include <bits/stdc++.h>
using namespace std;
char n;
int a, b;
int main() {
  cin >> a >> b;
  for (int s = 0; s < a; s++) {
    cin >> n;
    if (int(n) < 0 || int(n) > 9) {
      cout << "No" << endl;
      return 0;
    }
  }
  cin >> n;
  if (n != '-') {
    cout << "No" << endl;
    return 0;
  }
  for (int s = 0; s < b; s++) {
    cin >> n;
    if (int(n) < 0 || int(n) > 9) {
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
  return 0;
}
