In the circuit shown in the figure, two ideal batteries and three resistors are joined between two junctions, X at the top and Y at the bottom. The left branch has an $18\ \text{V}$ battery in series with a $2\ \Omega$ resistor, the right branch has a $6\ \text{V}$ battery in series with a $2\ \Omega$ resistor, and the middle branch is a single $1\ \Omega$ resistor. Both batteries have their positive terminals towards X. The current through the $1\ \Omega$ resistor, in amperes, is ____.

Fig. 1: Three branches between junctions X and Y: an 18 V battery with a 2 ohm resistor, a 1 ohm resistor, and a 6 V battery with a 2 ohm resistor, both batteries with their positive terminals towards X.