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