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