public static Integer composition(Matrix A){
        Integer I=0;

        boolean b = A.getN() == A.getM();
        if(!b) return null;
        int n = A.getN();

        int [] pi = new int[n+1];
        for(int i = 1; i<=n; i++)
               pi[i]=i;

        Rojok rj = new Rojok(n);
        func(1,n,pi,rj, I, A);
        return I;
    }