fun main () : nothing
	var r : char[32];
	fun reverse (ref s : char[]) : nothing
		var i, l : int;
		{
			l <- strlen(s);
			i <- 0;
			while i < l do {
				r[i] <- s[l-i-1];
				i <- i+1;
			}
			r[i] <- '\0';
		}
	{
		reverse("\n!dlrow olleH");
		puts(r);
	}