#include <bits/stdc++.h>
int main() {
  int a, b;
  std::cin >> a >> b;
  std::string s;
  std::cin >> s;
  for (int i = 0; i <= a + b; i++) {
    if ((i == a && s[a] != '-') || i - '0' < 0 || i - '0' > 9) {
      std::cout << "No\n";
      return 0;
    }
  }
  std::cout << "Yes\n";
  return 0;
}
