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#include <bits/stdc++.h>
using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    string a, b, res;
    cin >> a >> b >> res;
    int n = a.size();
    
    long long result = 0;
    int consec = 0;
    int carry = 0;
    for(int i=n-1; i>=0; i--) {
        int cur = (a[i]-'0') + (b[i]-'0') - (res[i]-'0');
        if(cur + carry == 10)           //ex: '6 + 9 (+0) = 5' or '6 + 9 (+1) = 6', where (+1) means carry and (+0) means no carry
            carry = 1;
        else if(cur == 10) {            //remove previous carry
            carry = 1;
            consec = 0;
        }
        else if(cur + carry == 0) {     //ex: '4 + 2 (+0) = 6' or '4 + 2 (+1) = 7'
            carry = 0;
            consec += 1;
            result += consec;
        }
        else if(cur == 0) {             //remove previous carry
            carry = 0;
            consec = 1;
            result += consec;
        }
        else {          //failure
            consec = 0;
            carry = 0;
        }
    }
    cout << result << "\n";

    return 0;
}