老鼠

#include <stdio.h>


int main(viod){
int old = 2, first = 0, second = 0, third = 0,i = 0,count = 0;
for (i = 0; i < 20; i++)
{
old = old + third;
third = second;
second = first;
first = old;
}
count = old + first + second + third;
printf("%d\n",count);
system("pause");

}