Main.cc: In function ‘long long int find(long long int, long long int)’:
Main.cc:11:9: error: ‘s’ was not declared in this scope
ans=s(n,m/2)%n;
^
Main.cc: In function ‘int main()’:
Main.cc:21:8: error: ‘s’ was not declared in this scope
ans=(s(n,n-1)+1)%n;
^