text: let countingSundays = (firstYear, lastYear) => {
  
      let sundayCount = 0
      let currentYear
      let currentMonth
  
      /* Number of days for each month in the year */
      let daysInMonth = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
  
      /* Starting Day of Week -> 0 is sunday, 6 is saturday. 
          Requires lookup to work from given year
      */
      let startingDayOfMonth = new Date(firstYear, 0, 1).getDay()
  
      for(currentYear = firstYear; currentYear <= lastYear; currentYear++){
  
          /* If the current year meets the conditions to be a leap year, then edit the 
              daysInMonth array so that feb has 29 days 
                  - The current year is divisble by 4 (divides by 4 with no remainder) and isn't a century
                      (divides by 100 without a remainder)
                  - Or the current year divides by 400 without a remainder
          */
          if((currentYear % 4 === 0 && currentYear % 100 != 0 )|| currentYear % 400 == 0){
              daysInMonth[2] = 29
          }else{
              daysInMonth[2] = 28
          }
  
          /* Go through each month */
          for(currentMonth = 1; currentMonth <= 12; currentMonth++){
  
              /* If the starting day of the month is a Sunday, then add 1 to the sunday count */
              if(startingDayOfMonth === 0){
                  sundayCount = sundayCount + 1
              }
  
              /* Calculate the starting day for the next month */
              console.log('Starting day of ' + currentMonth + ' ' + currentYear + ' is ' + startingDayOfMonth)
              startingDayOfMonth = (startingDayOfMonth + daysInMonth[currentMonth] % 7) % 7
          }
      }
      
      return sundayCount
  }
  
  /* Check Solution */
  console.log('Result is ' + countingSundays(1901, 2000))