import java.util.*;
import java.io.*;
class GFG
{
static int countOnes(int arr[], int n)
{
int low = 0, high = n - 1;
while(low <= high)
{
int mid = (low + high) / 2;
if(arr[mid] == 0)
low = mid + 1;
else
{
if(mid == 0 || arr[mid - 1] == 0)
return (n - mid);
else
high = mid -1;
}
}
return 0;
}
public static void main(String args[])
{
int arr[] = {0, 0, 1, 1, 1, 1}, n = 6;
System.out.println(countOnes(arr, n)); // OUTPUT : 4
}
}