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