issue in deleting last element of vector in a loop

In the below code if I try to remove any element except last one the code works fine . But if I try to delete last element it throws run time error . Not sure why ?

#include <iostream>
#include <string>
#include <vector>
using namespace std;
int main()
{
    vector<string> s;
    s.push_back("Jacob");
    s.push_back("Jamal");
    s.push_back("Joseph");
    s.push_back("Janardan");
    vector<string>::iterator it;

    for(it = s.begin(); it != s.end() ; it++)
        cout<<*it<<endl;

    for(it = s.begin(); it != s.end() ; it++)
        if(*it == "Janardan")
           s.erase(it);  

    for(it = s.begin(); it != s.end() ; it++)
        cout<<*it<<endl;

    return 0;
}