#include <stdio.h>

int  a,
     b = 1000,
     c,
     d,
     f;



///////////////////////////////////////////////////////////////////////////
int main()                                                               //
{

    printf("Books: ");
    scanf ("%d",  &a);

    d = a % 7;
    f = a / 7;

    for(int for_a = 0; for_a < f; for_a++)
    {
        for(int for_b = 0, b = 1000; for_b < 7; for_b++, b -= 55)
        {
            c += b;
        }
    }

    b = 1000;

    for(int for_a = 0; for_a < d; for_a++, b -= 55)
    {
        c += b;
    }
    printf("%d\n", c);

return 0;
}