#include <bits/stdc++.h>
int main(void) {
  int a, b;
  std::string s;
  std::cin >> a >> b >> s;
  int end = a;
  for (int i = 0; i < end; ++i) {
    if (!isdigit(s[i])) {
      std::cout << "No" << std::endl;
      return 0;
    }
  }
  if (s[end] != '-') {
    std::cout << "No" << std::endl;
    return 0;
  }
  end += b + 1;
  for (int i = a; i < end; ++i) {
    if (!isdigit(s[i])) {
      std::cout << "No" << std::endl;
      return 0;
    }
  }
  std::cout << "Yes" << std::endl;
  return 0;
}
