#include <bits/stdc++.h>
using namespace std;
int main()
{
	double x, n;
	cin >> n;
	if (n <= 20)
        x = n * 1.68;
	else
        x = n * 1.98;
	cout << fixed << setprecision(2) << x;
	return 0;
}//代码已AC

已AC，放心

#include<bits/stdc++.h>
using namespace std;
int main()
{
    double n;
    cin >> n;
    if(n <= 20)
    {
        cout << fixed << setprecision(2) << n * 1.68;
    }
    else
    {
        cout << fixed << setprecision(2) << n * 1.98;
    }
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int main()
{
    double c;
    cin >> c;
    if (c <= 20)
    {
        c = c * 1.68;
        printf("%.2f",c);
    }
    else
    {
        c = c * 1.98;
        printf("%.2f",c);
    }
    return 0;
}//A

#include<bits/stdc++.h>
using namespace std;
int main()
{
    double x;
    cin>>x;
    if (x<=20)
        cout<<fixed<<setprecision(2)<<x*1.68;
    else
        cout<<fixed<<setprecision(2)<<x*1.98;
    return 0;
}

    if(n > 20)
    {
        cout << fixed << setprecision(2) << n * 1.98;
    }
    else
    {
        cout << fixed << setprecision(2) << n * 1.68;
    }