#include <bits/stdc++.h>
constexpr long long int INF = std::numeric_limits<long long int>::max();
constexpr long long int NINF = std::numeric_limits<long long int>::min();
using namespace std;
void solve() {
  long long int A, B;
  string S;
  cin >> A >> B >> S;
  for (long long int i = 0; i < S.size(); i++) {
    if (S[i] == '-' && i != A) {
      cout << "No" << endl;
      return;
    } else if (i == A) {
      cout << "No" << endl;
      return;
    }
  }
  cout << "Yes" << endl;
}
signed main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  solve();
  return 0;
}
