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