function testBrackets(input) {
    let bracketsObj = {
        '{':'}',
        '[':']',
        '(': ')'
    }
    let bracketKeys = Object.keys(bracketsObj)
    
    const stack = []
    for(str of input){
        if (bracketKeys.includes(str)){
            stack.push(str)
        } else if (bracketsObj[stack.pop()] !== str){
            return false
        }
    }
    
    return stack.length == 0
}