View tc74hc157p datasheet:

TC74HC157P IL00 C-MOS QUAD 2-LINE-TO-1-LINE DATA SELECTOR/MULTIPLEXER —TOP VIEW— INH Y0 Y1 YC X0 X1 XC 2 V0 IN IN IN OUT IN IN OUT 3 V1 VC 4 16 15 14 13 12 11 10 9 VDD 5 W0 1 1 6 W1 WC 7 0 0 0 0 1 1 11 X0 10 X1 XC 9 GND 1 2 3 4 5 6 7 8 A V0 V1 VC W0 W1 WC Y0 14 IN IN IN OUT IN IN OUT 13 Y1 YC 12 CONT. IN ON INH A CHANNEL A INH 0 0 0 115 0 : LOW LEVEL 0 1 1 1 : HIGH LEVEL 1 x GND x : DON’T CARE