import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int n = scanner.nextInt();
if (n <= 3500) {
System.out.println(n);
} else {
for (int i = 3600; i <= 100000; i += 100) {
int B = 0;
int A = i - 3500;
if (A > 80000) {
B += (A - 80000) * 0.45;
}
if (A > 55000) {
B += (Math.min(80000, A) - 55000) * 0.35;
}
if (A > 35000) {
B += (Math.min(55000, A) - 35000) * 0.30;
}
if (A > 9000) {
B += (Math.min(35000, A) - 9000) * 0.25;
}
if (A > 4500) {
B += (Math.min(9000, A) - 4500) * 0.20;
}
if (A > 1500) {
B += (Math.min(4500, A) - 1500) * 0.10;
}
B += Math.min(A, 1500) * 0.03;
if (B + n == i) {
System.out.println(i);
return;
}
}
}
}
}
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