ABC111A - AtCoder Beginner Contest 999

問題：A - AtCoder Beginner Contest 999

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

#define REP(i, n) for (int i = 0; i < (n); ++i)

int main(void) {
    string n;
    
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> n;
    REP(i, n.length()) {
        if (n[i] == '1') {
            n[i] = '9';
        } else if (n[i] == '9') {
            n[i] = '1';
        }
    }
    
    cout << n << "\n";
    return 0;
}