C++, Order map content based on second iter

I have map as below

string word;
int occurance;
std::map< std::string, std::map<string, int> > map;
map[word]["count"] = occurance;

map output using iterator.

for(auto outer_iter=map.begin(); outer_iter!=map.end(); ++outer_iter) {
        for(auto inner_iter=outer_iter->second.begin(); inner_iter!=outer_iter->second.end(); ++inner_iter) {
            std::cout << outer_iter->first << '\t'  << inner_iter->second << std::endl;
        }
    }

I want to display map by ordering the inner_iter->second value.

How can I do it?