/in/foo.cc: In function 'int main()':
/in/foo.cc:19:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(int len=2;len<2*N;len++)
  ^~~
/in/foo.cc:26:4: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
    long long Ans=0;
    ^~~~