foo.c:1:1: warning: data definition has no type or storage class
    1 | a=input()
      | ^
foo.c:1:1: warning: type defaults to 'int' in declaration of 'a' [-Wimplicit-int]
foo.c:1:3: warning: implicit declaration of function 'input' [-Wimplicit-function-declaration]
    1 | a=input()
      |   ^~~~~
foo.c:1:3: error: initializer element is not constant
foo.c:2:1: error: expected ',' or ';' before 'b'
    2 | b=input()
      | ^
foo.c:4:33: error: empty character constant
    4 | print(a,'+',b,'+',c,'=',a+b,sep='')
      |                                 ^~

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