#include <stdio.h>

int main() {
    long long N;
    scanf("%lld", &N);

    long long lanterns = N / 500; 
    long long remaining = N % 500;
    long long banners = remaining / 5; 

    long long festivity_points = (lanterns * 1000) + (banners * 5);

    printf("%lld\n", festivity_points);
    return 0;
}