address

int fib(int n){
    if(n == 0)
        return 0;
    if(n == 1)
        return 1;
    int a[n+1];
    a[0] = 0;
    a[1] = 1;
    for(int i = 2; i<=n; i++)
        a[i] = (a[i-1] + a[i-2])%1000000007;
    return a[n];
}