#include <stdio.h>

int main()
{
    float money;
    scanf("%f", &money);
    if (money >= 5000)
    {
        money = 0.6 * money;
    }
    else if (money >= 2000)
    {
        money = 0.7 * money;
    }
    else if (money >= 500)
    {
        money = 0.8 * money;
    }
    else if (money >= 100)
    {
        money = 0.9 * money;
    }
    printf("%.1f", money);
    return 0;
}