#include <bits/stdc++.h>
using namespace std;
int main() {
  cin.tie(0);
  cout.tie(0);
  ios::sync_with_stdio(false);
  int A, B;
  cin >> A >> B;
  string S;
  cin >> S;
  for (long long i = 0; i < S.size(); ++i) {
    if ((i == A and S[i] != '-') or (S[i] < '0' or S[i] > '9')) {
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
}
