import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int ans = -1;
        for (int i=1;i<=5;i++) {
            int x = sc.nextInt();
            if (i != x) ans = i;
        }
        System.out.println(ans);
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int ans = -1;
        for (int i=1;i<=5;i++) {
            int x = sc.nextInt();
            if (i != x) ans = i;
        }
        System.out.println(ans);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int ans = -1;
        for (int i=1;i<=5;i++) {
            int x = sc.nextInt();
            if (i != x) ans = i;
        }
        System.out.println(ans);
    } main {
        Scanner sc = new Scanner(System.in);
        int ans = -1;
        for (int i=1;i<=5;i++) {
            int x = sc.nextInt();
            if (i != x) ans = i;
        }
        System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int ans = -1; ans -1 1 for (int i=1;i<=5;i++) {
            int x = sc.nextInt();
            if (i != x) ans = i;
        } int i=1; int i=1; i 1 i<=5 i 5 i++ i++ i {
            int x = sc.nextInt();
            if (i != x) ans = i;
        } {
            int x = sc.nextInt();
            if (i != x) ans = i;
        } int x = sc.nextInt(); x sc.nextInt() sc.nextInt sc if (i != x) ans = i; i != x i x ans = i ans i System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int ans = -1;
        for (int i=1;i<=5;i++) {
            int x = sc.nextInt();
            if (i != x) ans = i;
        }
        System.out.println(ans);
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int ans = -1;
        for (int i=1;i<=5;i++) {
            int x = sc.nextInt();
            if (i != x) ans = i;
        }
        System.out.println(ans);
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int ans = -1;
        for (int i=1;i<=5;i++) {
            int x = sc.nextInt();
            if (i != x) ans = i;
        }
        System.out.println(ans);
    }
}