#include <stdio.h>

int main() {
    int n;
    scanf("%d", &n);//输入
    int a = n / 1000;
    n %= 1000;
    int b = n / 100;
    n %= 100;
    int c = n / 10;
    n %= 10;
    int d = n / 1;

    d *= 1000;
    c *= 100;
    b *= 10;
    a *= 1;

    int sum = a + b + c + d;//总和

    printf("%04d\n", sum);
    return 0;
}