#include <bits/stdc++.h>
int main() {
  int A, B;
  std::string S;
  std::cin >> A >> B >> S;
  if (S[A] == '-') {
    auto rest = S.erase(A, 1);
    try {
      std::stoi(rest);
      std::cout << "Yes" << std::endl;
    } catch (...) {
      std::cout << "No" << std::endl;
    }
  } else {
    std::cout << "No" << std::endl;
  }
  return 0;
}
