function biggerIsGreater(w) {
    let s = w.split("");
    let index = -1;
    let n = w.length;
    
    for(let i = n-2; i>=0;i--){
        if(s[i] < s[i+1]){
            index = i;
            break;
        }
    }
    
    if(index === -1){
        return "no answer"
    }else{
        for(let i = n-1; i> index; i--){
            if(s[i] > s[index]){
                swap(index, i, s);
                break;
            }
        }
        reverse(index+1, n-1, s)
    }
    
    return s.join("");
    
    function swap(w1, w2, s){
        let temp = s[w1];
        s[w1] = s[w2];
        s[w2] = temp;
    }

    function reverse(start, end, s){
        while(start <= end){
            swap(start, end, s);
            start++;
            end--;
        }
    }
}