#include <stdio.h>

main() {
    int a = 27;
    int b = 13;

    printf("a:%d \n",a);
    printf("b:%d \n",b);

    a=a+b;
    b=a-b;
    a=a-b;

    printf("a:%d \n",a);
    printf("b:%d \n",b);
}