#include <bits/stdc++.h>
int main() {
  bool flag = true;
  int a, b;
  std::string s;
  std::cin >> a >> b >> s;
  for (int i = 0; i < s.length(); i++) {
    if (i == a) {
      if (s[i] == '-') {
        flag &= true;
      }
    }
    int t = s[i] - '0';
    if (0 <= t && t <= 9) {
      flag &= true;
    }
  }
  if (flag) {
    std::cout << "Yes" << std::endl;
  } else {
    std::cout << "No" << std::endl;
  }
}
