The P in the chip number is fine. The important part is that it is a 74LS, not 74S, 74, 74HC, 74C, etc. LS means that is operates within a digital input/output of 5V. The 74C and 74HC are CMOS versions and operate at 3.3V, which would run hot on 5V and even burn out faster than a LS series, the others operate at other voltage ranges.