Two dice throwing game issue

My program needs to throw 2 dices and when both are 6 it gets out of the loop and show me how many times it tries, but for some reason I get very wierd try numbers like, most of them are "it took 1-3 tries".. Help plz.

public class SheshBesh {
public static void main(String[] args){

    int r1 = 0;
    int r2 = 0;
    int tries = 0;

    while (r1 != 6 && r2 != 6) {
        r1 = (int)(Math.random() * 6) + 1;
        r2 = (int)(Math.random() * 6) + 1;
        tries = tries + 1;
    }

    System.out.println("Shesh-Besh apears... it took " + tries + " tries.");


}

}