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