#include <bits/stdc++.h>
int main() {
  using std::string;
  int a, b;
  std::cin >> a >> b;
  string s;
  std::cin >> s;
  if (s[a] == '-') {
    if (std::all_of(s.begin(), s.begin() + a - 1, isdigit)) {
      if (std::all_of(s.begin() + a + 1, s.end(), isdigit))
        std::cout << "Yes" << std::endl;
    }
  } else
    std::cout << "No" << std::endl;
  return 0;
}
