Two cells are connected between points \( A \) and \( B \) as shown. Cell \( 1 \) has emf of \( 12 \, \text{V} \) and internal resistance of \( 3 \, \Omega \). Cell \( 2 \) has emf of \( 6 \, \text{V} \) and internal resistance of \( 6 \, \Omega \). An external resistor \( R \) of \( 4 \, \Omega \) is connected across \( A \) and \( B \). The current flowing through \( R \) will be ______ \( \text{A} \).
