skyline.cpp: In function 'long long unsigned int rec(long long unsigned int, long long unsigned int)':
skyline.cpp:23:1: warning: no return statement in function returning non-void [-Wreturn-type]
23 | }
| ^
skyline.cpp: At global scope:
skyline.cpp:24:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
24 | main(){
| ^
skyline.cpp: In function 'int main()':
skyline.cpp:11:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
11 | #define scan1(a) scanf("%lld",&a);
| ~~~~~^~~~~~~~~~~
skyline.cpp:26:5: note: in expansion of macro 'scan1'
26 | scan1(n)
| ^~~~~