#include<iostream>
using namespace std;
int main()
{
	int n,n1,p,c,i;
	cout<<"n="; cin>>n;
	n1=n;
	c=0;
	while(n>0) 
	{
		c++;
		n=n/10;
	}
	p=1;
	for(i=1;i<=c/2;i++) p=p*10;
	n=n1/(p*10)*p+n1%p;
	cout<<n;
	return 0;
}


sau 

#include<iostream>
using namespace std;
int main()
{
	int n,nr,r,x,i;
	cout<<"n="; cin>>n;
	nr=0;
	x=n;
	while(x>0)
	{ 
		nr++;
		x=x/10;
	}
	r=0;
	for(i=1;i<=nr/2;i++) 
	{ 
		r=r*10+n%10;
		n=n/10;
	}
	n=n/10;
	while(r>0)
	{
		n=n*10+r%10;
		r=r/10;
	}
	cout<<n;
}