#include<bits/stdc++.h>
#define M 101010
#define N 1010
#define ll long long
using namespace std;

ll re(){
    ll s = 0, f = 1; char c = getchar();
    for(; !isdigit(c); c = getchar())
        if(c == '-') f = -1;
    for(;  isdigit(c); c = getchar())
        s = s * 10 + c - '0';
    return f * s;
}

int main(){
	int d;
	d = re();
	double mon;
	if(d <= 150)mon = 0.4463*d;
	else if(d >= 151&&d <= 400)mon = 66.945 + (d - 150)*0.4663;
	else if(d >= 401)mon = 182.52 + (d - 400)*0.5663;
	printf("%.1f",mon);
	

	return 0;
}