function abn(nt) {
myReference = document.getElementById('nota');
myReference.style.visibility="hidden";
myReference = document.getElementById('notb');
myReference.style.visibility="hidden";
myReference = document.getElementById('notc');
myReference.style.visibility="hidden";
myReference = document.getElementById('notd');
myReference.style.visibility="hidden";
myReference = document.getElementById('note');
myReference.style.visibility="hidden";
myReference = document.getElementById('notf');
myReference.style.visibility="hidden";
myReference = document.getElementById('notg');
myReference.style.visibility="hidden";
myReference = document.getElementById('noth');
myReference.style.visibility="hidden";
myReference = document.getElementById('noti');
myReference.style.visibility="hidden";
myReference = document.getElementById('notj');
myReference.style.visibility="hidden";
myReference = document.getElementById('notk');
myReference.style.visibility="hidden";
myReference = document.getElementById('notl');
myReference.style.visibility="hidden";
myReference = document.getElementById('notm');
myReference.style.visibility="hidden";
myReference = document.getElementById('notn');
myReference.style.visibility="hidden";
myReference = document.getElementById('noto');
myReference.style.visibility="hidden";
myReference = document.getElementById('notp');
myReference.style.visibility="hidden";
myReference = document.getElementById('notq');
myReference.style.visibility="hidden";
myReference = document.getElementById('notr');
myReference.style.visibility="hidden";
myReference = document.getElementById('nots');
myReference.style.visibility="hidden";
myReference = document.getElementById('nott');
myReference.style.visibility="hidden";
myReference = document.getElementById('not' + String.fromCharCode(nt));
myReference.style.visibility="visible";
}

function cen(nt) {
myReference = document.getElementById(nt);
myReference.style.visibility="hidden";
}