#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int a, b;
  string s;
  cin >> a >> b >> s;
  for (int i = 0; i < s.size(); ++i) {
    if (i == a && s[i] != '-') {
      cout << "No"
           << "\n";
      return 0;
    } else if (s[i] - '0' >= 10 || s[i] - '0' < 0) {
      cout << "No"
           << "\n";
      return 0;
    }
  }
  cout << "Yes"
       << "\n";
}
