Unable to parse the date in the format "M/d/yyyy H:m:s" using DateTime.ParseExact(String, String, IFormatProvider)

I am working on a windows phone silverlight application.I have a requirement where in I want to parse the date string of format "M/d/yyyy H:m:s" (eg: 3/18/2015 14:4:5) to DateTime struct.
This is what I tried:
     
     string dateString = "3/18/2015 14:4:5";
     string format = @"M/d/yyyy H:m:s";
     CultureInfo provider = CultureInfo.InvariantCulture;
     DateTime.ParseExact(dateString,format,provider);

But I am getting the following output:
03-18-2015 14:04:05

Required Output:
3/18/2015 14:4:5

I want the DateSeparator to be "/" and doesn't want an addition of extra '0' to any of the parameters like day,month,year,minutes etc to make it two digits.