function apriSoluzione(num){
	var myTable = document.getElementById("sol_"+num);
	var myTables = document.getElementsByTagName("TABLE");

	for(var i=0; i<myTables.length; i++){
		if(myTables[i].id.substring(0,4) == 'sol_'){
			myTables[i].className = "hidden";
		}
	}

	myTable.className = "storici";
}