ошибка Return функция() + значение;

messagebox(shorten_price(10000));



function floor_division(int x, int y)
{
int quotient = 0;
while(x>=y) {x = x - y; quotient++;}
return quotient;
}

function shorten_price(int price)
{
if (price < 1000) return format(price);
if(modulo(price, 500) != 0) return format(price);
if(price < 1000000) {int re=floor_division(price, 1000); return format(re) + "к";}
return format(floor_division(price, 1000000)) + "кк";
}

function modulo(int x, int y)
{
while(x>=y) x = x - y;
return x;
}