C++ STL Multimap

#include<iostream>
#include<map>
#include<iterator>
using namespace std;
int main()
{
    multimap<string, int>a;
    multimap<string, int> :: iterator r;

    a.insert(make_pair("Aubdur Rob Anik", 73));
    a.insert(make_pair("Mahadi Al Hadi", 72));
    a.insert(make_pair("Aubdur Rob Anik", 73));
    a.insert(make_pair("Aubdur Rob Anik", 93));
    a.insert(make_pair("Aubdur Rob Anik", 83));

    for(r=a.begin(); r!=a.end(); r++)
    {
        cout << r->first << " --> " << r->second << endl;
    }

    return 0;
}