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

#define all(a) (a).begin(), (a).end()

typedef long long ll;
typedef vector<int> vi;
typedef vector<long long> vll;
typedef pair<int,int> pii;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    // freopen("./a.txt", "r", stdin);

    string as,bs,cs;
    cin>>as>>bs>>cs;
    vi a(as.size()), b(bs.size()), c(cs.size());
    for (int i=0; i<as.size(); i++) {
        a[i] = as[i]-'0';
        b[i] = bs[i]-'0';
        c[i] = cs[i]-'0';
    }

    ll res = 0;
    int st=a.size()-1, en=a.size()-1;
    vector<bool> carries(a.size(),false);
    while (en>=0 || st>=0) {
        bool last_carry = false;
        int no_carries = 0;

        while (en>=0 && (a[en]+b[en]+last_carry)%10==c[en]) {
            last_carry = a[en]+b[en]+last_carry>=10;
            if (last_carry) {
                no_carries++;
                carries[en] = true;
            }
            en--;
        }
        res += st-en-no_carries;

        while (st > en) {
            if (!carries[st]) {
                st--;
                res += st-en-no_carries;
            } else {
                no_carries--;
                for (int i=st-1; i>en; i--) {
                    if (a[i]+b[i]>=1) break;
                    if (!carries[i]) break;
                    carries[i] = false;
                    no_carries--;
                }
                st--;
            }
        }

        if (st>=0 && (a[st]+b[st])%10 != c[st]) {
            st--;
            en--;
        }
    }

    cout<<res<<'\n';

    return 0;
}