#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <stack>
#include <queue>
#include <string>
#include <climits>
#include <cmath>
#include <ctype.h>
using namespace std;

#define fst ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define sp " "
#define nl "\n"
#define yes cout << "YES\n"
#define no cout << "NO\n"
#define sd cout
#define imx INT_MAX
#define imn INT_MIN
#define pb push_back
#define vi vector<int>
#define vl vector<ll>
#define elif else if
#define fi(k, l) for (int i = k; i < l; i++)
#define as(v) sort(v.begin(), v.end())
#define asr(a, n) sort(a, a + n)
#define ds(v) sort(v.rbegin(), v.rend())
#define F first
#define S second

typedef long long ll;

int main() {
    fst;
    int t=(10*11)/2;
    int sum=0,x;
    fi(0,9){
        cin>>x;
        sum+=x;
    }
    cout<<t-sum;
    return 0;
}