chessboard.cpp: In function 'll solve(long long int, bool)':
chessboard.cpp:26:18: warning: unused variable 'cl' [-Wunused-variable]
26 | bool cl;
| ^~
chessboard.cpp: At global scope:
chessboard.cpp:35:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
35 | main(){
| ^
chessboard.cpp: In function 'int main()':
chessboard.cpp:36:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
36 | scanf("%lld%lld",&n,&m);
| ~~~~~^~~~~~~~~~~~~~~~~~
chessboard.cpp:37:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
37 | for(int i=0;i<m;i++)scanf("%lld%lld%lld%lld",&rect[i].x,&rect[i].y,&rect[i].x2,&rect[i].y2),rect[i]._minus();
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~