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


int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    string a, b, c;
    cin >> a;
    cin >> b;
    cin >> c;
    long long wyn = 0;
    int x, y , z, c1, c2, s, p, w;
    for(int j = a.size() - 1; j >= 0; j--){
            p = 0; w = 0;
            for(int i = j; i >= 0; i--){
            c1 = a[i] - '0';
            c2 = b[i] - '0';
            s  = c1 + c2 + p;
            p = s / 10;
            if (s %10 != c[i] - '0') break;
            if (p == 0) w++;
            }
        wyn = wyn + w;
    }

    cout << wyn;
  return 0;
}