#include <bits/stdc++.h>
using namespace std;
int GCD(const int& a, const int& b) {
  const int& _a = max(a, b);
  const int& _b = min(a, b);
  if (_a % _b == 0) {
    return _b;
  } else {
    return GCD(_b, _a % _b);
  }
}
int LCM(const int& a, const int& b) {
  const int& _a = max(a, b);
  const int& _b = min(a, b);
  return (_a * _b) / (GCD(_a, _b));
}
int main() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  bool is_ok = true;
  for (int i = 0; i < s.size(); i++) {
    if (i == a) {
      is_ok = (s[a] == '-') ? true : false;
    } else {
      if (s[i] == '0' || s[i] == '1' || s[i] == '2' || s[i] == '3' ||
          s[i] == '4' || s[i] == '5' || s[i] == '6' || s[i] == '7' ||
          s[i] == '8' || s[i] == '9') {
        is_ok = true;
      } else {
        is_ok = false;
      }
    }
  }
  cout << (is_ok ? "Yes" : "No") << endl;
  return 0;
}
