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: Runtime Error)

import java.util.ArrayDeque;
import java.util.Deque;
import java.util.stream.IntStream;

public class Main {
    public static int h;
    public static int w;
    public static int k;
    public static int x2;
    public static int y2;
    public static String[] c;
    public static Long res[][];
    public static Deque<StackElement> stack = new ArrayDeque<>();

    static class StackElement {
        int x;
        int y;
        int mukiid;
        long count;

        public StackElement(int xin, int yin, long countin, int mukiidin) {
            x = xin;
            y = yin;
            count = countin;
            mukiid = mukiidin;
        }

        public String toString() {
            return "(" + x + " " + y + " " + count + ")";
        }
    }

    public static void main(String[] args) {
        var sc = new java.util.Scanner(System.in);
        h = sc.nextInt();
        w = sc.nextInt();
        k = sc.nextInt();

        var x1 = sc.nextInt() - 1;
        var y1 = sc.nextInt() - 1;
        x2 = sc.nextInt() - 1;
        y2 = sc.nextInt() - 1;
        c = new String[h];
        IntStream.range(0, h).forEach(i -> {
            c[i] = sc.next();
        });
        res = new Long[h][];
        IntStream.range(0, h).forEach(i -> {
            res[i] = new Long[w];
        });
        stack.push(new StackElement(x1, y1, 0L, -1));
        res[x1][y1] = 0L;
        while (!stack.isEmpty()) {
            StackElement e = stack.pollLast();
            search(e.x, e.y, e.count, e.mukiid);
            if (res[x2][y2] != null) {
                break;
            }
        }
        if (res[x2][y2] != null) {
            System.out.println(res[x2][y2]);
        } else {
            System.out.println(-1);
        }
    }

    public static boolean isHasu(int x, int y) {
        if (x < 0 || x >= h || y < 0 || y >= w) {
            return true;
        } else {
            return c[x].charAt(y) == '@';
        }
    }

    public static boolean isSeachable(int x, int y, long count) {
        boolean isHasu = isHasu(x, y);
        if (!isHasu && res[x][y] != null && count < res[x][y]) {
            return false;
        } else if ((!isHasu && (res[x][y] == null || count <= res[x][y]))) {
            return true;
        } else {
            return false;
        }
    }

    public static void search(int x, int y, long count, int mukiid) {

        if (x2 != x || y2 != y) {
            long nextCount = count + 1;

            if (mukiid != 2) {
                for (int i = x + 1; i <= x + k; i++) {
                    if (!isSeachable(i, y, nextCount)) {
                        break;
                    }
                    res[i][y] = nextCount;
                    stack.push(new StackElement(i, y, nextCount, 1));
                }
            }
            if (mukiid != 1) {
                for (int i = x - 1; i >= x - k; i--) {
                    if (!isSeachable(i, y, nextCount)) {
                        break;
                    }
                    res[i][y] = nextCount;
                    stack.push(new StackElement(i, y, nextCount, 2));
                }
            }
            if (mukiid != 4) {
                for (int i = y + 1; i <= y + k; i++) {
                    if (!isSeachable(x, i, nextCount)) {
                        break;
                    }
                    res[x][i] = nextCount;
                    stack.push(new StackElement(x, i, nextCount, 3));
                }
            }
            if (mukiid != 3) {
                for (int i = y - 1; i >= y - k; i--) {
                    if (!isSeachable(x, i, nextCount)) {
                        break;
                    }
                    res[x][i] = nextCount;
                    stack.push(new StackElement(x, i, nextCount, 4));
                }
            }

        }
    }
}