#include<stdio.h>
int main()
{
    int y,n;
    scanf("%d",&y);
    if(1<=y<=5)
    {   
        n=5;
        printf("%d""%",n);
    }
    else if(6<=y<=10)
    {   
        n=10;
        printf("%d%",n);
    }
    else if(y<=11)
    {   
        n=15;
        printf("%d%",n);
    }
    else
        printf("Invalid Input")
        
}