#include <bits/stdc++.h>
int A, B;
std::string S;
int main() {
  std::cin >> A >> B >> S;
  for (int i = 0; i < S.length(); ++i) {
    if (i < A && S[i] == '-') {
      std::cout << "No" << std::endl;
      return 0;
    }
    if (i == A && S[i] != '-') {
      std::cout << "No" << std::endl;
      return 0;
    }
  }
  std::cout << "Yes" << std::endl;
  return 0;
}
