invers

#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;
long double x,y;

void cb(long double st,long double dr)
{
    x=(st+dr)/2;
    long double f=sin(x)+sin(2*x)+x;
    if(abs(f-y)<=0.000000001)
    {
        cout<<setprecision(8)<<x;
        return;
    }
    if(f<y)
        cb(x,dr);
    if(f>y)
        cb(st,x);
}

int main()
{
    cin>>y;
    cb(0,1);
    return 0;
}