C++ :

#include<stdio.h>

int main()
{
	int a,b,c,d,e,f,g;
	scanf("%d",&a);
	b=a/10000;
	c=a/1000%10;
	d=a/100%10;
	e=a/10%10;
	f=a%10;
	g=f*10000+e*1000+d*100+c*10+b;
	printf("%d",g);
	return 0;
}

Pascal :

var s:string;

v,flag:int64;

c,i,len:longint;

begin

read(s);

val(s,v,c);

if (v=0) then write(0) else

if ((v<0) and (s[length(s)]='0')) then delete(s,length(s),1) else

if ((v>0) and (s[length(s)]='0')) then delete(s,length(s),1);

len:=length(s)+1;

repeat

if s[len]='0' then delete(s,len,1);

dec(len);

until s[len]<>'0';

if (v<0) then

begin

delete(s,1,1);

flag:=1;

end;

if flag=1 then write('-');

for i:=length(s) downto 1 do

write(s[i]);

end.