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