def isBalanced(s):
    # Write your code here
    stack = []
    left_brackets = '([{'
    bracket_map = {')': '(', ']': '[', '}': '{'}
    for c in s:
        if c in left_brackets:
            stack.append(c)
        else:
            if stack and stack[-1] == bracket_map[c]:
                stack.pop()
            else:
                return 'NO'
    return 'NO' if stack else 'YES'