#include<iostream>
#include<queue>
#include<vector>
#define int long long
using namespace std;
priority_queue<int,vector<int>,less<int>>q;
vector<int>vc[20];
signed main() {
	int n;
	while(cin>>n) {
		for(int i=1; i<=9; i++) {
			vc[i].clear();
		}
		for(int i=1; i<=n; i++) {
			int a;
			cin>>a;
			int num=10;
			for(int j=1; j<=9; j++) {
				int tm=a%num;
				vc[j].push_back(tm);
				num*=10;
			}
		}
//		vector<int>::iterator it1;
		int tm=10;
		int ans=0;
		for(int i=1; i<=9; i++) {
			int l=0;
			for(auto it:vc[i]) {
				l++;
				int bz=tm-it;
//				cout<<bz<<" ";
				int it1=lower_bound(vc[i].begin()+l,vc[i].end(),bz)-vc[i].begin();
//cout<<it1<<endl;
				if(it1>vc[i].size())continue;
				if(it1<l)it1=l;
				ans+=vc[i].size()-it1;
			}
			tm*=10;
//			cout<<endl;
		}
		cout<<ans<<endl;
	}
}