View Code of Problem 23

#include<stdio.h>
int main()
{
	int i,n;
	long int sum=0,sum1=1,sum2=2;
	while(scanf("%d",&n)!=EOF)
	{
		if(n==0||n>90)break;
		sum=0,sum1=1,sum2=2;
		for(i=2;i<n;i++)
		{
			sum=sum1+sum2;
			sum1=sum2;
			sum2=sum;
		}
		if(n==1)
		printf("1\n");
		else if(n==2)
		printf("2\n");
		else
		printf("%ld\n",sum);
	}
}