#include <bits/stdc++.h>
using namespace std;
string s;
long long a[1000005], d = 0;
map<long long, long long> dem, dem1;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
cin >> s;
for(int i = 0; i < s.size(); i++) a[i + 1] = s[i] - 48;
dem1[0] = 1;
for(int i = 1; i <= s.size(); i++){
dem[a[i]]++;
long long x = dem[1] - dem[0];
d = d + dem1[x];
dem1[x]++;
}
cout << d;
return 0;
}
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