23 lines
375 B
C++
23 lines
375 B
C++
#include <bits/stdc++.h>
|
|
|
|
using namespace std;
|
|
|
|
int main() {
|
|
int n;
|
|
int sum = 0;
|
|
int pre = 0;
|
|
while (cin >> n) {
|
|
if (n == 0) break;
|
|
if (n == 1) {
|
|
sum++;
|
|
pre = 0;
|
|
}
|
|
if (n == 2) {
|
|
pre += 2;
|
|
sum += pre;
|
|
}
|
|
}
|
|
cout << sum << endl;
|
|
return 0;
|
|
}
|