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