import java.util.Vector;
import java.lang.Integer;
import java.lang.Boolean;

class Matrix extends Vector<Vector<Integer>> {
    mul(m) {
        var ret = new Matrix();
        var i = 0;
        while(i < size()) {
            var v1 = this.elementAt(i);
            var v2 = new Vector<Integer>();
            var j = 0;
            while(j < v1.size()) {
                //var erg = 0;
                //var k = 0;
                //while(k < v1.size()) {
                    //erg = erg + v1.elementAt(k)
                    //         * m.elementAt(k).elementAt(j);
                    //k++; }
                //v2.addElement(new Integer(erg));
                j++; }
            ret.addElement(v2);
            i++; }
        return ret;
    }
}