/in/foo.c:1:1: warning: data definition has no type or storage class
n=str(input())
^
/in/foo.c:1:1: warning: type defaults to 'int' in declaration of 'n' [-Wimplicit-int]
/in/foo.c:1:3: warning: implicit declaration of function 'str' [-Wimplicit-function-declaration]
n=str(input())
^~~
/in/foo.c:1:7: warning: implicit declaration of function 'input' [-Wimplicit-function-declaration]
n=str(input())
^~~~~
/in/foo.c:1:3: error: initializer element is not constant
n=str(input())
^~~
/in/foo.c:2:1: error: expected ',' or ';' before 'n'
n=n.repkace(" ","%20")
^