栈为什么开了unsigned long long还错

#include<iostream>
using namespace std;
unsigned long long a[100005];
int main(){
	unsigned long long n,m,top=0,x;
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>m;
		for(int j=1;j<=m;j++){
			string s;
			cin>>s;
			if(s=="push"){
				cin>>x;
				a[++top]=x;
			}else if(s=="pop"){
				if(top==0) cout<<"Empty"<<endl;
				else top--;
			}else if(s=="query"){
				if(top==0) cout<<"Anguei!"<<endl;
				else cout<<a[top]<<endl;
			}else if(s=="size") cout<<top<<endl;
			
		}
	}
	return 0;
}