#include<bits/stdc++.h> using namespace std; double f(double xx){ return pow(xx,5)-15*pow(xx,4)+85*pow(xx,3)-225*pow(xx,2)+274*xx-121; int main() { const double x=0.000001; for(double y=1.5;y<=2.4;y+=x){ if(f(y)*f(y+x)<=0){ cout<<fixed<<setprecision(6)<<y; break; } } return 0; }