include <stdio.h>

int main() {

double c; int a; scanf("%d",&a);

if(a<=150) {

c=a*0.4463;

} else if(a>150&&a<=400) {

c=150*0.4463+(a-150)*0.4663;

} else {

c=150*0.4463+(400-150)*0.4663+(a-400)*0.5663;

} printf("%.1lf",c); return 0; }