#include<stdio.h>
#include<string.h>

int a[202],b[202],c[202];

void adun(int a[],int b[])
{
    int i,t=0;
    for(i=1;i<=a[0]||i<=b[0]||t;++i)
    {
        t+=a[i]+b[i];
        a[i]=t%10;
        t/=10;
    }
    a[0]=i-1;
}

int main()
{
    freopen("nunta.in","r",stdin);
    freopen("nunta.out","w",stdout);
    int n,i;
    scanf("%d",&n);
    if(n==1)
    {
        printf("1\n");
        return 0;
    }
    a[0]=a[1]=1;
    b[0]=b[1]=1;
    for(i=1;i<n;++i)
    {
        memcpy(c,b,sizeof(b));
        adun(b,a);
        memcpy(a,c,sizeof(c));
    }
    for(i=b[0];i>=1;--i)
        printf("%d",b[i]);
    printf("\n");
    return 0;
}