5.83

$$ \sum_{j,k} (-1)^{j+k}\binom{j+k}{k+l}\binom{r}{j}\binom{n}{k}\binom{s+n-j-k}{m-j} $$ $$ \begin{aligned} 0+1+2+3&=r \ 4+5+6+7&=n \ 8+9&= s-r \ 0+1&= ......