{
        cout<<"Choose a mask (1-8): ";
        int mask;
        cin>>mask;
        if(mask==1)return 0;
        if(mask==2)return 1;
        if(mask==3)return 2;
        if(mask==4)return 3;
        if(mask==5)return 4;
        if(mask==6)return 5;
        if(mask==7)return 0;//
        if(mask==8)return 7;
        if(mask==0)return customMask(structuringElements);
        cout<<endl<<"No such mask exists. Proceeding with default mask No. 1.";
        return 1;
    }