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