#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B;
  cin >> A >> B;
  string S;
  cin >> S;
  for (int i = 0; i < S.length(); i++) {
    if (A > i) {
      if (S[i] == '-') {
        cout << "No" << endl;
        return 0;
      }
    } else if ((A + 1) == i) {
      if (S[i] != '-') {
        cout << "No" << endl;
        return 0;
      }
    } else {
      if (S[i] == '-') {
        cout << "No" << endl;
        return 0;
      }
    }
  }
  cout << "Yes" << endl;
}
