#include <bits/stdc++.h>
using namespace std;
int main() {
  char trash;
  double x[4], y[4];
  while (cin >> x[0] >> trash >> y[0]) {
    double p, q, r;
    for (int i = 1; i < 4; i++) {
      cin >> trash >> x[i] >> trash >> y[i];
    }
    p = ((y[1] - y[0]) * (x[3] - x[0]) / (x[1] - x[0])) + y[0];
    q = ((y[2] - y[1]) * (x[3] - x[1]) / (x[2] - x[1])) + y[1];
    r = ((y[2] - y[0]) * (x[3] - x[0]) / (x[2] - x[0])) + y[0];
    if (x[0] == x[2]) {
      if (x[0] > x[1]) {
        if (x[0] > x[3]) {
          cout << "NO" << endl;
        } else {
          if ((p < y[3] && q > y[3]) || (p > y[3] && q < y[3])) {
            cout << "YES" << endl;
          } else {
            cout << "NO" << endl;
          }
        }
      } else {
        if (x[0] < x[3]) {
          cout << "NO" << endl;
        } else {
          if ((p < y[3] && q > y[3]) || (p > y[3] && q < y[3])) {
            cout << "YES" << endl;
          } else {
            cout << "NO" << endl;
          }
        }
      }
    } else if (x[0] == x[1]) {
      if (x[0] > x[2]) {
        if (x[0] < x[2]) {
          cout << "NO" << endl;
        } else {
          if (x[0] > x[1]) {
            if (q > y[3]) {
              cout << "YES" << endl;
            } else {
              cout << "NO" << endl;
            }
          } else {
            if (q < y[3]) {
              cout << "YES" << endl;
            } else {
              cout << "NO" << endl;
            }
          }
        }
      } else {
        if (x[0] > x[2]) {
          cout << "NO" << endl;
        } else {
          if (x[0] > x[1]) {
            if (q > y[3]) {
              cout << "YES" << endl;
            } else {
              cout << "NO" << endl;
            }
          } else {
            if (q < y[3]) {
              cout << "YES" << endl;
            } else {
              cout << "NO" << endl;
            }
          }
        }
      }
    } else if (x[1] == x[2]) {
      if (x[0] > x[1]) {
        if (x[1] > x[3]) {
          cout << "NO" << endl;
        } else {
          if (x[2] > x[1]) {
            if (p < y[3]) {
              cout << "YES" << endl;
            } else {
              cout << "NO" << endl;
            }
          } else {
            if (p > y[3]) {
              cout << "YES" << endl;
            } else {
              cout << "NO" << endl;
            }
          }
        }
      } else {
        if (x[1] < x[3]) {
          cout << "NO" << endl;
        } else {
          if (p < y[3]) {
            cout << "YES" << endl;
          } else {
            cout << "NO" << endl;
          }
        }
      }
    } else {
      if (r > y[1]) {
        if (r > y[3]) {
          cout << "NO" << endl;
        } else {
          if ((p < y[3] && q > y[3]) || (p > y[3] && q < y[3])) {
            cout << "YES" << endl;
          } else {
            cout << "NO" << endl;
          }
        }
      } else {
        if (r < y[3]) {
          cout << "NO" << endl;
        } else {
          if ((p < y[3] && q > y[3]) || (p > y[3] && q < y[3])) {
            cout << "YES" << endl;
          } else {
            cout << "NO" << endl;
          }
        }
      }
    }
  }
}
