#include <stdio.h>
int fun(int a, int t);
int main()
{
?int i, j, b,t;
?printf("請輸入最后一天所剩的桃子數和吃桃子的天數\n");
?scanf("%d%d", &b,&t);
?j = fun(b, t);
?printf("%d", j);
}
int fun(int a, int t)
?{
?int sum;

?if (t == 1)
? sum=2 * t + a;
?else
? sum=2 * fun(a, t-1) + a;

?return sum;
}