#include <bits/stdc++.h> using namespace std; #define endl "\n" #define pb push_back #define int long long #define fi first #define se second const int N = 3e5 + 5, M = 1e9 + 7, LG = 20; int n , A[N] , pr[N]; void solve(){ cin >> n; for (int i=1 ; i<=n ; i++){ cin >> A[i]; if (A[i] == 2) A[i] = -1; pr[i] = pr[i-1] + A[i]; } int ans = 0; map<int,int> mp; mp[0] = 1; for (int i=1 ; i<=n ; i++){ ans += (i-mp[pr[i]]); mp[pr[i]]++; } cout << ans << endl; } signed main(){ // freopen("" , "r" , stdin); // freopen("" , "w" , stdout); // cout << setprecision(30); ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); int ts = 1; // cin >> ts; while(ts--){ solve(); } }