/in/foo.cc: In function 'int main()':
/in/foo.cc:8:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<st.size();i++)
              ~^~~~~~~~~~
/in/foo.cc:8:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(int i=0;i<st.size();i++)
  ^~~
/in/foo.cc:10:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
   cout<<ans;
   ^~~~
/in/foo.cc:10:12: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
   cout<<ans;
            ^