#include <iostream>
using namespace std;

int main() {
    int num;
    cin >> num;

    int original = num;
    int reversed = 0;

    // 反转四位数
    while (num > 0) {
        reversed = reversed * 10 + num % 10;
        num /= 10;
    }

    // 计算差值
    int difference = original - reversed;
    cout << difference << endl;

    return 0;
}    
/**************************************************************
	Problem: 1702
	User: linmiaoling
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/