#include <bits/stdc++.h>
using namespace std;
using P = pair<int, int>;
using ll = long long;
int main() {
  string s;
  int a, b;
  cin >> a >> b >> s;
  string ans = "Yes";
  for (int i = 0; i < (int)(s.size()); i++) {
    if (i == a && s[i] != '-')
      ans = "No";
    else if (s[i] < '0' || s[i] > '9')
      ans = "No";
  }
  cout << ans << endl;
  return 0;
}
