#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
using namespace std;
using namespace __gnu_pbds;
 
using ordered_set = tree<
    pair<int, int>,
    null_type,
    less<pair<int, int>>,
    rb_tree_tag,
    tree_order_statistics_node_update
>;
 
int main() {
    int n;
    string s;
    cin >> n >> s;
 
    ordered_set X;
 
    X.insert({0, 0});
 
    int prefix = 0;
    long long ans = 0;
 
    for (int j = 0; j < n; j++) {
        prefix += (s[j] == '1' ? 1 : -1);
 
        ans += X.order_of_key({prefix, 0});
 
        X.insert({prefix, j + 1});
    }
 
    cout << ans << '\n';
}

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

NQoxMTAxMA==

5
11010