九十分代码！！！

哪位大佬帮忙修一下呀！！

 
#include<bits/stdc++.h>
using namespace std;
#define int long long
#define double long double

struct birth{
	string s;
	int y,m,d;
}k[1005];
bool cmp(birth a,birth b){
	if(a.y==b.y){
        if(a.m==b.m) return a.d<b.d;
        else return a.m<b.m;
    }
	else return a.y<b.y;
}
int n;
signed main(){
	cin>>n;
	for(int i=0;i<n;i++) cin>>k[i].s>>k[i].y>>k[i].m>>k[i].d;
	sort(k,k+n,cmp);
	for(int i=0;i<n;i++) cout<<k[i].s<<"\n";
	
	return 0;
}