Number of equal values in vector - how to get it

I have this vector object

std::vector<std::vector<int> > Status(anyNumber, std::vector<int>(anyNumber, 0.)); // Matrix with entries 0/1 for status off/on

which gets filled with zeros and ones. What is the best way to find how many ones there are in Status in C/C++? Maybe one can do some kind of sorting?