#include <bits/stdc++.h>
using namespace std;
using ll=long long;
 
int main() {
	// your code goes here
	ll n;
	cin>>n;
	vector<ll>arr(n+1,0),p(n+1,0);
	for(ll i=1;i<=n;i++){
		cin>>arr[i];
		p[i]=p[i-1]+arr[i];
	}
	ll k;
	cin>>k;
	ll c=0;
	// for(ll i=0;i<n;i++){
	// 	sum=0;
	// 	for(ll j=i;j<n;j++){
	// 		sum+=arr[i];
	// 		ll len=j-i+1;
	// 		if(sum%k==len)c++;
 
	// 	}
	// }
	//p[j]-p[i-1]=j-i+1
	//p[j]-j=p[i-1]-i+1
	unordered_map<ll,ll>mp;
	mp[0]=1;
	for(ll i=1;i<=n;i++){
		ll x=(p[i]%k-i%k+k)%k;
		if(mp.count(x)){
			c+=mp[x];
		}
		mp[x]++;
	}
	cout<<c<<endl;
 
	return 0;
}

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NgowIDEgNCAyIDMgNQ==

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