#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 < s.size(); i++)
    if (!(s[i] == '-' || (s[i] >= '0' && s[i] <= '9'))) cnt = 1;
  if (cnt == 1) cout << "No" << endl;
  if (cnt == 0)
    if (s[a] == '-')
      cout << "Yes" << endl;
    else
      cout << "No" << endl;
  return 0;
}
