I need help with code 1409:

#include <stdio.h>
int main()
{
    int a,b,c,d;
    scanf("%d%d",&a,&b);
    printf("%d\n",c=10-a,d=10-b, c+d<10);
    scanf("%d%d",&c,&d);
    getchar(), getchar();
    return 0;
}

You don't understand this problem.

Let Harry shooted A cans and Larry shooted B cans, then together they shooted A+B-1 cans.
So Harry didn't shoot (A+B-1)-A = B-1 cans, and Larry didn't shoot (A+B-1)-B = A-1 cans. And it's the answer!