#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin >>n;
    long long a,ans=0,cnt[205]={0};
    for(int i=0;i<n;i++){
        cin >>a;
        cnt[a%200]+=1;
    }
    for(int i=0;i<200;i++){
        if(cnt[i]>1){
            ans+=(cnt[i]-1)*cnt[i]/2;
        }
    }
    cout <<ans <<endl;
    return 0;
}
#include<bits/stdc++.h>
#include <iterator>
#include <iostream>
#include <numeric>
#include <math.h>
#define ll long long
#define ull long
#define mpa make_pair
#define pb push_back
#define ff first
#define pii pair<ll,ll>
#define dd double
#define trace(x) cerr << #x << " : " << x << endl
#define ss second
#define boost ios_base::sync_with_stdio(0)
#define forp(i,a,b) for(ll i=a;i<=b;i++)
#define rep(i,n)    for(ll i=0;i<n;++i)
#define ren(i,n)    for(ll i=n-1;i>=0;i--)
#define forn(i,a,b) for(ll i=a;i>=b;i--)
#define all(c) (c).begin(),(c).end()
#define tr(c,i) for(typeof((c).begin()) i = (c).begin(); i != (c).end();
#define sc(x) scanf("%lld",&x)
#define clr(x,val) memset(x,val,sizeof(x))
#define pr(x) printf("%lld\n",x) 
#define pdd pair<dd,dd>
#define read_arr(a,n) for(ll i=1;i<=n;i++)cin>>a[i];
#define init_arr(a,n) for(ll i=1;i<=n;i++)a[i]=n-i+1;
#define prec(x) cout<<fixed<<setprecision(x)
#define fre freopen("input.txt","r",stdin),freopen("C:/Users/HP/OneDrive/Desktop/compi_prog/output.txt","w",stdout)
#define arr array 
using namespace std;
void solve(ll tc){
	ll n,e;
	cin>>n;
	vector<ll> cnt(200,0);
	ll ans=0;


	for(ll i=1;i<=n;i++){
		cin>>e;
		e%=200;
		ans=ans+cnt[e];
		cnt[e]++;
	}
	cout<<ans;


}

int main(){

	boost;
	


	ll t=1;
	t=1;

	
	ll tc=1;

	while(t--){
		solve(tc);
		tc++;
	}
	

}
	
	
 
 
 
 


	

	







	
	

	
	




		


    
	


		