#include #include using namespace std; int rec(int number) { if(number == 0) { return 0; } int last_digit = number % 10; if(last_digit == 9) { last_digit = 7; } return rec(number / 10) * 10 + last_digit; } int main() { int number; cin >> number; cout << rec(number) << endl; return 0; } // rec(9592) = rec(959) * 10 + 2 = 757 * 10 + 2 = 7572 // rec(959) = rec(95) * 10 + 7 = 75 * 10 + 7 = 757 // rec(95) = rec(9) * 10 + 5 = 7 * 10 + 5 = 75 // rec(9) = rec(0) * 10 + 7 = 0 * 10 + 7 = 7 // rec(0) = 0