#include <stdio.h>

int main() {
    long long N;
    scanf("%lld", &N);
    long long lanterns = N / 500;
    long long remaining_tokens = N % 500;
    long long banners = remaining_tokens / 5;
    long long festivitypoints = (lanterns * 1000) + (banners * 5);
    printf("%lld\n", festivitypoints);
    
    return 0;
}