function missingNumbers(arr, brr) {
    
    const groupA = arr.reduce((acc, n) => {
        acc[n] = (acc[n] || 0) + 1;
        return acc;
    }, {});
    
    const groupB = brr.reduce((acc, n) => {
        acc[n] = (acc[n] || 0) + 1;
        return acc;
    }, {});
    
    var missing = [];
    for(const nu of brr){
        if(groupA[nu] !== groupB[nu] && missing.indexOf(nu) < 0){
            missing.push(nu);
        }
    }
   
    return missing.sort(function(a, b) {
        return a - b;
    });
}