#include <iostream>
#include <cmath>
using namespace std;

int main() {
    int B[10] = {};
    for(int i=0; i<9; ++i) {
        cin >> B[i];
    }
    B[9] = 11;
    for(int i=0; i<9; ++i) {
        if(B[i]+1 != B[i+1]) {
            cout << B[i]+1 << endl;
        }
    }
}