#include <stdio.h>
#include <math.h>

int main(){
    float hours;
    int fee;
    sacnf("%f",&hours);
    if(hours<=0||hours>24){
        printf("Invalid input");
        return 0;
        
    }
    fee =10;
    if(hours>1){
        fee+=ceil(hours-1)*5;
    }printf("%d",fee);
    return 0;
}