#include <bits/stdc++.h>
using namespace std;
const double PI = 3.141592654;
void fast() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL), cout.tie(NULL);
}
long long gcd(long long a, long long b) { return !b ? a : gcd(b, a % b); }
long long lcm(long long a, long long b) { return (a / gcd(a, b)) * b; }
int main() {
  fast();
  string s, ss, f, ff;
  int x, y;
  cin >> x >> y >> s;
  if (s.size() == x + y + 1 && s.find('-') != -1) {
    cout << "Yes" << endl;
  } else
    cout << "No" << endl;
  return 0;
}
