#include <iostream>

using namespace std;

int main() {
  double X, E, E10, summary = 0, summaryE = 0, summaryE10 = 0;
  int N, amountE = 0, amountE10 = 0;

  cout << "Enter X: ";
  cin >> X;

  if (X <= -1 || X >= 1) {
    cout << "X must be in (-1;1).";
    return 0;
  }

  cout << "Enter E: ";
  cin >> E;
  if (E < 0) {
    cout << "Your E is negative but must be nonnegative. E will be absoulte.";
    E = abs(E);
  }
  E10 = E / 10;

  cout << "Enter N: ";
  cin >> N;
  if (N < 0) {
    cout << "N must be nonnegative";
    return 0;
  }

  double term = 1;
  for (int i = 0; i < N; i++) {
    summary += term;
    if (abs(term) > E10) {
      if (abs(term) > E) {
        summaryE += term;
        amountE++;
      }
      summaryE10 += term;
      amountE10++;
    }
    term *= -X;
  }

  cout << endl << "Results:" << endl;
  cout << "1/(1+x) = " << 1.0 / (1.0 + X) << endl;
  cout << "Summary of N(" << N << ") elements is equal to " << summary << endl;
  cout << "Summary of (" << amountE
       << ") elements, which absolute value is higher than E(" << E
       << ") equals to " << summaryE << endl;
  cout << "Summary of (" << amountE10
       << ") elements, which absolute value is higher than E10(" << E10
       << ") equals to " << summaryE10 << endl;
  return 0;
}