#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  string ans = "Yes";
  if (s.at(a) != '-') {
    ans = "No";
  }
  int tmp;
  for (int i = a + 1; i <= a + b; i++) {
    if (s.at(i) == '-') ans = "No";
  }
  cout << ans << endl;
  return 0;
}
