#include <bits/stdc++.h>
template <typename T>
T gcd(T a, T b) {
  return b == 0 ? a : gcd(b, a % b);
}
template <typename T>
T lcm(T a, T b) {
  return a * b / gcd(a, b);
}
template <typename T>
T clamp(T val, T min, T max) {
  return val < min ? min : (max < val ? max : val);
}
char capitalize(char c) {
  return static_cast<char>(std::toupper(static_cast<unsigned char>(c)));
}
using namespace std;
signed main(void) {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long num = 0;
  bool flag = false;
  long long a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  long long hyphen = 0;
  for (auto it = s.begin(); it != s.end(); ++it) {
    if (*it == '-') hyphen++;
  }
  if (hyphen == 1) flag = true;
  cout << (flag ? "Yes" : "No") << endl;
  return 0;
}
