#include <bits/stdc++.h>

using namespace std;

int main() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  bool valid = true;
  for (int i = 0; i < s.size(); i++) {
    if (!((i == a && s[i] == '-') || (i != a && isdigit(s[i])))) valid = false;
  }
  cout << (valid ? "Yes" : "No") << endl;
}
