#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  bool flag = true;
  for (int i = 0; i <= a + b; i++) {
    if (i == a && s.at(i) != '-')
      flag = false;
    else if (s.at(i) == '-')
      flag = false;
  }
  if (flag)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
