Number of pixels in AOI using Google Earth Engine JavaScript API

Question

I'm trying to calculate the fraction of snow cover and compare it to a time series. For this I need the total number of pixels with and without snow in an area of interest. I can get this # of pixels for one day, but I can't do it for a longer period like in a time series.

I leave here the code that I am using.

https://code.earthengine.google.com/4f04d770b3dfa9036a7a4a427cee3a94

Map.centerObject(z6);
Map.addLayer(z6);

var modis = ee.ImageCollection('MODIS/006/MYD10A1'); 
var mod11a2 = modis.filterDate( '2016-01-01', '2017-03-01'); //'2023-02-25'

var modLSTday = mod11a2.select('NDSI_Snow_Cover');

print(modLSTday);

var allDates = modLSTday.aggregate_array('system:time_start');

var allDates = allDates.map(function(date){
  return ee.Date(date).format().slice(0,10);
  });
  
print("allDates", allDates);

var snowCoverVis = {
  min: 0.0,
  max: 100.0,
  palette: ['black', '0dffff', '0524ff', 'ffffff'],
};

var snowcover_lst = modLSTday.toList(modLSTday.size());

var image = ee.Image(ee.List(snowcover_lst).get(359)); // EL número ".get (151) significa el # de imagen en la colección 

var c = image.reduceRegion({
  reducer: ee.Reducer.count(),
  geometry: z6
  });

print("numero de pixeles como nieve", c);

var image2 = ee.Image(ee.List(snowcover_lst).get(359));

var count = image2.reduceRegion({
  reducer: ee.Reducer.count(),
  geometry: z6, // subtract half the scale from geometry
  scale: 500,
  maxPixels: 1e9
})

print("numero de pixeles de Z6", count)



Export.image.toDrive({
  image: image,
  description: 'Nieve23',
  //Folder: SWE_DayMet,
  //band: "swe",
  region: z6,
  crs:'EPSG:4326',
  scale: 500,
  maxPixels: 1e13
  });