#include<stdio.h>
int main()
{
    long long m;
    long long n,t;
    scanf("%lld",&m);
    n=m/1000;
    t=m-n*1000;
    if(n>t)
        printf("%lld",m);
    else
        printf("%lld",t*1000+n);
    return 0;
}

/**************************************************************
	Problem: 1631
	User: admin
	Language: C
	Result: Accepted
	Time:28 ms
	Memory:1144 kb
****************************************************************/