What is the difference between ldc.i4.s and ldc.i4?

I was studying about the Intermediate Language for C#(IL) and came across the following piece of code:- ``` //Add.il //Add Two Numbers .assembly extern mscorlib {} .assembly Add { .ver 1:0:1:0 } .module add.exe .method static void main() cil managed { .maxstack 2 .entrypoint ldstr "The sum of 50 and 30 is = " call void [mscorlib]System.Console::Write (string) ldc.i4.s 50 ldc.i4 30 add call void [mscorlib]System.Console::Write (int32) ret } ``` I am a beginner in understanding IL but I know the meaning of these very basic instructions used in the `Main`, in the above example. My question is that Is there any difference between the instructions `ldc.i4.s` which is used to load 50 and the instruction `ldc.i4` which is used to load 30 onto the evaluation stack. How does the compiler decide which instruction to use(out of these two) and when?