# Gate Input Cost **The number of inputs to basic logic gates in an implementation.** *Gate input cost*, GIC, is typically *only* considered in circuits with basic [[Boolean Algebra#Logical operations|logic gates]] - the AND, OR, and NOT gates. It can be found graphically from a logic diagram or numerically using [[Boolean Function#Sum-of-products or product-of-sums form|sum-of-products or product-of-sums equations]]. In a sum-of-products or product-of-sums equation, the GIC is the sum of - *Every [[Boolean Function#^2dba35|literal]]* appearance - The number of *distinct complemented* literals - The number of *non-literal* [[Boolean Function#^5aa5f5|terms]] > [!Example] $F=AB+\bar{C}(D+E)$ > There are clearly $5$ literals; one of the literals are *complemented*, and the three *non-literal* terms are $AB$, $D+E$, and $\bar{C}(D+E)$. > Thus, the gate input cost is $9$. > ![[GateInputCostCircuit.svg|500]] ## Gate input cost of other gates ### NAND and NOR The equivalent GIC of [[Universal Gate|NAND and NOR]] gates is $3$. ![[NANDNOREquivalentGIC.svg]] ### XOR and XNOR The equivalent GIC of [[Exclusive Disjunction|XOR]] and [[Material Biconditional|XNOR]] gates is $7$. ![[XORXNOREquivalentGIC.svg]]