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