def isBalanced(s):
    # Write your code here
    opening = []
    for bracket in s:
        if bracket in ["(", "{", "["]:
            opening.append(bracket)
        else:
            try:
                pair = opening.pop()
                if pair=="(" and bracket!=")":
                    return 'NO'
                if pair=="{" and bracket!="}":
                    return 'NO'
                if pair=="[" and bracket!="]":
                    return 'NO'
            except Exception:
                return 'NO'
    if opening:
        return 'NO'
    else:
        return 'YES'