#include <iostream>
#include <fstream>


#define INPUT_FILE "input.txt"
#define OUTPUT_FILE "output.txt"

using namespace std;

int main () {
    bool end = false;

    int N;
    double somma;

    fstream infile, outfile;

    infile.open(INPUT_FILE, fstream::in);
    outfile.open(OUTPUT_FILE, fstream::out);

    if(!infile.is_open()) {
        cerr << "Error opening file " << INPUT_FILE << endl;
        return -1;
    }

    if(!outfile.is_open()) {
        cerr << "Error opening file " << OUTPUT_FILE << endl;
        return -1;
    }

    while (!end) {

        infile >> N;

        if (infile.eof()) {
            cout << "end of input, exit!" << endl;
            end = true;
        }

        else if(infile.fail()) {
            cerr << "Error reading N from file " << INPUT_FILE << endl;
            end = true;
        }



    }


    infile.close();
    outfile.close();
}