#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) {
    s.erase(a, 1);
    for (const auto n : s) {
      if (!isdigit(n)) {
        std::cout << "No" << std::endl;
        return -1;
      }
    }
    std::cout << "Yes" << std::endl;
  } else
    std::cout << "No" << std::endl;
}
