#include <bits/stdc++.h>
using namespace std;
 
int main() {
	int n;
	cin>>n;
 
	vector<int> numbers(n);
 
	for(auto& number: numbers){
		cin>>number;
	}
 
	int answer = 0;
 
	unordered_map<int,int> prefixSum;
 
	prefixSum[0] = 1;
 
	int sum = 0;
 
	for(int i=0; i<n; i++){
		sum += numbers[i];
 
 
		if(prefixSum.find(sum - i - 1) != prefixSum.end()){
			answer+=prefixSum[sum-i-1];
		}
 
		prefixSum[sum-i-1]++;
	}
 
	cout << answer;
 
	return 0;
}

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NQoxIDIgMyA0IDE=

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