#include <bits/stdc++.h>
int main() {
  int A, B;
  std::cin >> A >> B;
  std::string S;
  std::cin >> S;
  bool cond1 = S[A] == '-';
  bool cond2 = std::all_of(S.begin(), S.begin() + A,
                           [](char c) { return std::isdigit(c); });
  bool cond3 = std::all_of(S.begin() + A + 1, S.end(),
                           [](char c) { return std::isdigit(c); });
  std::cout << (cond1 && cond2 && cond3 ? "Yes" : "No") << std::endl;
}
