#include <bits/stdc++.h>
using namespace std;
long computeCompressionLoss(vector<int> featureMap) {
long long ans = 0;
long long run = 0;
for (int x : featureMap) {
if (x == 1) {
run++;
} else {
ans += run * (run + 1) / 2;
run = 0;
}
}
// last run (if array ends with 1s)
ans += run * (run + 1) / 2;
return ans;
}
int main() {
// your code goes here
int n;
cin >> n;
vector<int> v(n);
for (int i=0;i<n;i++) cin >> v[i];
cout << computeCompressionLoss(v) << endl;
return 0;
}
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