#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B, s_size;
  string s;
  cin >> A >> B >> s;
  s_size = s.size();
  bool fla = true;
  for (int i = 0; i < s_size; i++) {
    if (i < A) {
      if (s.at(i) < 48 or s.at(i) > 57) {
        fla = false;
        break;
      }
    } else if (i == A and s.at(i) != '-') {
      fla = false;
      break;
    } else {
      if (s.at(i) < 48 or s.at(i) > 57) {
        fla = false;
        break;
      }
    }
  }
  if (fla)
    cout << "Yes" << endl;
  else {
    cout << "No" << endl;
  }
}
