#include <iostream>
#include <string>
#include <cctype>
 
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;
      retrn 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;
}