Main.cc: In function ‘int main()’:
Main.cc:10:14: error: expected initializer before ‘==’ token
double nn==mm/500-2;
^~
Main.cc:13:20: error: ‘nn’ was not declared in this scope
int N=ceil(nn);
^~
Main.cc:13:20: note: suggested alternative: ‘n’
int N=ceil(nn);
^~
n