#include<stdio.h>

void main()
{
    int harry, larry;
    int sum;
    int harryleft, larryleft;

    scanf("%d%d", harry, larry);
    sum = (harry + larry)-1;
    harryleft = sum - harry;
    larryleft = sum - larry;
    printf("%d%d", harryleft, larryleft);

        return 0;
}

Here's the necessary changes:
int main()

scanf("%d%d", &harry, &larry);