#include <stdio.h>
void main () {
int i,n;long a=1,b=1;
printf("Enter n:\n");
scanf("%d",&n);
if(n<0) printf("Error input!");
else if(n>0&&n<=2) printf("%d个月的兔子总数为1\n",n);
else if(n>2) for(i=3;i<=n;i++)
{if(i%2==1)a=a+b;
else b=b+a;}
if(n>2&&n%2==1) printf("%d个月的兔子总数为%ld\n",n,a);
else if(n>2&&n%2==0)printf("%d个月的兔子总数为%ld\n",n,b);
}