#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  string ans = "No";
  for (int i = 0; i < s.size(); i++) {
    if ((i == a && s[i] == '-') && (i != a && s[i] != '-')) ans = "Yes";
  }
  cout << ans << endl;
}
