1176 The Closest Fibonacci Number

#include<iostream>

#include<cmath>

using namespace std;

int main(){

int n,fn,fn_1=1,fn_2=1;

cin>>n;

for(int i=2;;i++){

fn=fn_1+fn_2;

if(abs(fn-n)>=abs(fn_1-n)){

cout<<fn_1<<endl;

return 0;

}

fn_2=fn_1;

fn_1=fn;

}

return 0;

}