#include<iostream>
using namespace std;
int cnt = 0;
void check(double xa, double ya, double xb, double yb, double xc, double yc, double xd, double yd);
int main() {
    double xa, ya, xb, yb, xc, yc, xd, yd;
    char c; //comma
    while (cin >> xa >> c >> ya >> c >> xb >> c >> yb >> c >> xc >> c >> yc >> c >> xd >> c >> yd) {
        //多分4patternいらない
        check(xa, ya, xb, yb, xc, yc, xd, yd);
        if (cnt) {
            continue;
        }
        cnt = 0;
        check(xb, yb, xc, yc, xd, yd, xa, ya);
        if (cnt) {
            continue;
        }
        cnt = 0;
        check(xc, yc, xd, yd, xa, ya, xb, yb);
        if (cnt) {
            continue;
        }
        cnt = 0;
        check(xd, yd, xa, ya, xb, yb, xc, yc);
        if (cnt) {
            continue;
        }
        cnt = 0;
        cout << "NO" << endl;
    }
    return 0;
}
void check(double xa, double ya, double xb, double yb, double xc, double yc, double xd, double yd) {
    double tc = (xa - xb) * (yc - ya) + (ya - yb) * (xa - xc);
    double td = (xa - xb) * (yd - ya) + (ya - yb) * (xa - xd);
    if (tc * td < 0) {
        double ta = (xc - xd) * (ya - yc) + (yc - yd) * (xc - xa);
        double tb = (xc - xd) * (yb - yc) + (yc - yd) * (xc - xb);
        if (ta * tb < 0) {
            cout << "YES" << endl;
            cnt++;
        }
    } else { //square
        if ((xb - xa) * (xd - xa) + (yb - ya) * (yd - ya) == 0) {
            //cout << (xb - xa) * (xd - xa) + (yb - ya) * (yd - ya) << endl;
            if ((xc - xd) * (xc - xb) + (yc - yd) * (yc - yb) == 0) {
                //cout << (xc - xd) * (xc - xb) + (yc - yd) + (yc - yb) << endl;
                cout << "YES" << endl;
                cnt++;
            }
        }
    }
}


