import java.util.Vector;

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;
    }
}