foo.cc: In function 'int main()':
foo.cc:12:10: error: expected primary-expression before '!=' token
  while(n%!=1)
          ^~
foo.cc:14:2: error: expected ';' before 'for'
  for(int i=m;i<=n;i+=2)
  ^~~
foo.cc:14:14: error: 'i' was not declared in this scope
  for(int i=m;i<=n;i+=2)
              ^

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