#include <iostream>
#include <iomanip>
using namespace std;
int main()
{double add(double sum);
double returnnumber,inputnumber=0;
returnnumber=add(inputnumber);
cout<<"answer is:"<<setprecision(10)<<returnnumber<<endl;
return 0;
}
double add(double sum)
{
double first=1,second=1;
double a,b,t;
while (t>=0.0001||t<=-0.0001)
{sum=second+first;
a=sum/second;
b=second/first;
t=a-b;
first=second;
second=sum;
}
return (a);
}
