#include <iostream>

int main(int argc, char** argv) {
  int a, b;
  std::string str;
  std::cin >> a >> b;
  
  std::cin >> str;
  
  char* str_p = str.c_str();
  
  for (int i=0; i< str.length(); i++) {
    if (i<a && str_p[i] == '-') { std::cout << "No"; return -1; }
    if (i == a+1 && str_p[i] != '-') { std::cout << "No"; return -1;}
    if (i>a+1 && i <a+b+1 str_p[i] == '-') { std::cout << "No"; return -1; }
  }
  std::cout << "Yes" << std::endl;
  return 0;
}