foo.c:3:1: warning: data definition has no type or storage class
 a=int(input())
 ^
foo.c:3:1: warning: type defaults to 'int' in declaration of 'a' [-Wimplicit-int]
foo.c:3:3: error: expected expression before 'int'
 a=int(input())
   ^~~

自豪的采用 HydroJudger 进行评测(github.com/hydro-dev/HydroJudger)