Main.cc:39:9: error: ‘::main’ must return ‘int’
ll main(){
^
Main.cc: In function ‘int main()’:
Main.cc:42:7: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
scanf("%lld",&n);
~~~~~^~~~~~~~~~~
Main.cc:45:8: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
scanf("%lld",&a[i]);
~~~~~^~~~~~~~~~~~~~