Multimap STL implementation

/multimap stl;
//here multiple element can have the same key

//#include<bits/stdc++.h>
#include
#include
#include
using namespace std;

//insetr(),find(),erase() with logn complexity

int main()
{
multimap<char,string>m;

int n;
cin>>n;
for(int i=0;i<n;i++)

{
char ch;
string s;
cin>>ch>>s;
m.insert(make_pair(ch,s));

}

//erase
auto it=m.begin();
m.erase(it);

//try to print the entire map;
for(auto p:m)
{
cout<<p.first<<" -->"<<p.second<<endl;

}

//search for cat
auto f=m.find(“c”);
if(f->second==“cat”)
{
m.erase(f);

}

for(auto p:m)
{
cout<<p.first<<"–>"<<p.second<<endl;

}
return 0;
}
//the code is not working due to find() function,please help me to resolve the problem