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#include <bits/stdc++.h>
using namespace std;
string a, b, c;

int check(int id) {
  int val = 0;
  int carry = 0;
  for (int i = id; i >= 0; i--) {
    val = carry + a[i] - '0' + b[i] - '0';
    carry = val >= 10;
    val -= 10 * carry;
    if (val != c[i] - '0') {
      return -1;
    }
    if (carry == 0) {
      return i;
    }
  }
  if (val == c[0] - '0' and carry == 0) {
    return 0;
  }
  return -1;
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> a >> b >> c;
  long long ans = 0;
  long long cnt = 0;
  for (int i = a.size() - 1; i >= 0; i--) {
    int tmp = check(i);
    if (tmp != -1) {
      i = tmp;
      cnt++;
      ans += cnt;
    } else {
      cnt = 0;
    }
  }
  cout << ans;
}