import java.util.Scanner;
public class Main{
 public static void main(String[] args){
	Scanner stdIn = new Scanner(System.in);
   int a[] = new int[5];
    a[0] = stdIn.nextInt();
    a[1] = stdIn.nextInt();
    a[2] = stdIn.nextInt();
    a[3] = stdIn.nextInt();
    a[4] = stdIn.nextInt();
     if (a[0] == 0) {
       System.out.println("1");
     }
     if (a[1] == 0) {
       System.out.println("2");
     }
     if (a[2] == 0) {
       System.out.println("3");
     }
     if (a[3] == 0) {
       System.out.println("4");
     }
     if (a[4] == 0) {
      System.out.println("5");
     }
 }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz