A quadruple $(a, b, c, d)$ of distinct integers is said to be $\text{balanced}$ if $a + c = b + d$. Let $\mathcal{S}$ be any set of quadruples $(a, b, c, d)$ where $1 \leq a < b < d < c \leq 20$ and where the cardinality of $\mathcal{S}$ is $4411$. Find the least number of balanced quadruples in $\mathcal{S}$.

Let's think step by step and output the final answer within \boxed{}.
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