#include <iostream>
using namespace std;

int main() {
  int A, B;
  string s;
  bool flag = true;
  cin >> A >> B >> s;
  for (int i=0; i<A+B+1; i++) {
    if ((i!=A && s[i]=='-') || (i==A && s[i]!='-')) flag = false;
  }

  cout << (flag?"Yes":"No") << endl;
  return 0;
}
