Unexpected compilation error

I wrote this. doesn't matter what am I supposed to do with this. It just doesn't complie! Using G++ 4.9

#include <iostream>
#include <set>
#include <string>
using namespace std;

struct data {
    string s;
    int x, y;
};

int main() {

    int n;
    cin >> n;

    set <data> Set;
    for (int i = 0; i < n; i++) {
        data temp;
        cin >> temp.s >> temp.x >> temp.y;
        Set.insert(temp);
    }
    // Prints the size
    cout << Set.size() << endl;

    int cnt = 0;
    set <data> :: iterator it;
    for (it = Set.begin(); it != Set.end(); ++it)
        cout << (*it).s << (++cnt % 5 ? " " : "\n");

    return 0;
}