斐波那契数列

#include <stdio.h>

int fbla(int n)
{
    int f = 0, g = 1;
    while (n--)
    {
        g = g + f;
        f = g - f;
    }
    return g;
}

int main()
{
    int n;
    scanf("%d", &n);
    printf("%d\n", fbla(n));
}