#include <bits/stdc++.h>
using namespace std;
signed main() {
  string s;
  while (cin >> s) {
    s += ',';
    double d[10];
    long long p = 0;
    double d1 = 0, l = 1;
    bool b = 0;
    for (long long i = 0; i < s.size(); i++) {
      if (s[i] == ',') {
        d[p] = d1;
        p++;
        d1 = 0;
        b = 0;
        l = 1;
      } else if (s[i] == '.') {
        b = 1;
        l = 0.1;
      } else if (!b) {
        d1 = d1 * 10 + (s[i] - '0');
      } else {
        d1 += (s[i] - '0') * l;
        l /= 10;
      }
    }
    if (d[4] == d[0]) {
      if ((d[2] - d[0]) * (d[0] - d[6]) <= 0)
        cout << "NO\n";
      else {
        double k = (d[7] - d[3]) / (d[6] / d[2]), p = d[3] - d[2] * k;
        if ((k * d[0] + p - d[1]) * (d[5] - (k * d[4] + p)) <= 0)
          cout << "NO\n";
        else
          cout << "YES\n";
      }
    } else if (d[6] == d[2]) {
      if ((d[0] - d[2]) * (d[2] - d[4]) <= 0)
        cout << "NO\n";
      else {
        double k1 = (d[5] - d[1]) / (d[4] - d[0]), p1 = d[1] - d[0] * k1;
        if ((k1 * d[2] + p1 - d[3]) * (d[7] - (k1 * d[6] + p1)) <= 0)
          cout << "NO\n";
        else
          cout << "YES\n";
      }
    } else {
      double k1 = (d[5] - d[1]) / (d[4] - d[0]),
             k2 = (d[7] - d[3]) / (d[6] / d[2]);
      double p1 = d[1] - d[0] * k1, p2 = d[3] - d[2] * k2;
      if ((k1 * d[2] + p1 - d[3]) * (d[7] - (k1 * d[6] + p1)) <= 0)
        cout << "NO\n";
      else if ((k2 * d[0] + p2 - d[1]) * (d[5] - (k2 * d[4] + p2)) <= 0)
        cout << "NO\n";
      else
        cout << "YES\n";
    }
  }
}
