def abbreviation(a, b):
    # Write your code here
    results, valid, last = {''}, False, False
    for i, char in enumerate(a):
        new = set()
        last = i == len(a) - 1
        for result in results:
            less = len(result) < len(b)
            if char.isupper():
                if last: valid = result + char == b
                elif less: new.add(result + char)
            else:
                temp = result + char.upper()
                if last: valid = b == result or b == temp
                if not last:
                    new.add(result)
                    if less and b.startswith(temp): new.add(temp)
            if last and valid: return 'YES'
        results = new
    return 'NO'