#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  string c;
  cin >> a >> b >> c;
  for (int i = 0; i < a + b + 1; i++) {
    if (i != a) {
      if (c[i] != '1' && c[i] != '2' && c[i] != '3' && c[i] != '4' &&
          c[i] != '5' && c[i] != '6' && c[i] != '7' && c[i] != '8' &&
          c[i] != '9') {
        cout << "No" << endl;
        break;
      }
    } else {
      if (c[a] != '-') {
        cout << "No" << endl;
        break;
      }
    }
  }
  cout << "Yes" << endl;
}
