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