Problem:
Score : 100 points

Problem Statement

We have five variables x_1, x_2, x_3, x_4, and x_5.

The variable x_i was initially assigned a value of i.

Snuke chose one of these variables and assigned it 0.

You are given the values of the five variables after this assignment.

Find out which variable Snuke assigned 0.

Constraints

The values of x_1, x_2, x_3, x_4, and x_5 given as input are a possible outcome of the assignment by Snuke.

Input

Input is given from Standard Input in the following format:

x_1 x_2 x_3 x_4 x_5

Output

If the variable Snuke assigned 0 was x_i, print the integer i.

Sample Input 1

0 2 3 4 5

Sample Output 1

1

In this case, Snuke assigned 0 to x_1, so we should print 1.

Sample Input 2

1 2 0 4 5

Sample Output 2

3

Solution in Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;

// Solution
public class Main {
  private static Scanner in;
  private static PrintWriter out;
  private static final String INPUT = ""; // input file name

  /**
   * Interactive get next command
   */
  static int get(int pos) {
    out.println(pos + 1);
    out.flush();
    return ni();
  }

  static void solve() {
    int[] arr = new int[5];
    
    for (int i = 0; i < 5; i++) {
    	arr[i] = ni();
    }
    
    for (int i = 0; i < 5; i++) {
      if (arr[i] == 0) {
        out.println(i + 1);
      }
    }
  }

  public static void main(String[] args) throws Exception {
    long S = System.currentTimeMillis();
    in = INPUT.isEmpty() ? new Scanner(System.in) : new Scanner(INPUT);
    out = new PrintWriter(System.out);

    solve();
    out.flush();
    long G = System.currentTimeMillis();
    tr(G - S + "ms");
  }

  private static int ni() {
    return Integer.parseInt(in.next());
  }

  private static long nl() {
    return Long.parseLong(in.next());
  }

  // Math Utils
  private static int pi(int num, int pow) {
    int result = 1;

    while (pow > 0) {
      if (pow % 2 == 1) {
        result *= num;
      }

      num *= num;
      pow /= 2;
    }

    return result;
  }

  private static int pim(int num, int pow, int mod) {
    int result = 1;

    while (pow > 0) {
      if (pow % 2 == 1) {
        // keep collecting `odd` num in result
        result = (result * num) % mod;
      }

      num = (num * num) % mod;
      pow /= 2;
    }

    return result;
  }

  private static long pl(long num, long pow) {
    long result = 1;

    while (pow > 0) {
      if (pow % 2 == 1) {
        result *= num;
      }

      num *= num;
      pow /= 2;
    }

    return result;
  }

  private static long plm(long num, long pow, long mod) {
    long result = 1;

    while (pow > 0) {
      if (pow % 2 == 1) {
        // keep collecting `odd` num in result
        result = (result * num) % mod;
      }

      num = (num * num) % mod;
      pow /= 2;
    }

    return result;
  }

  static void tr(Object... o) {
    if (!INPUT.isEmpty())
      out.println(Arrays.deepToString(o));
  }
}