#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
struct hugeint
{
        int len,a[210];
            hugeint()
                    {
                                len=0;
                                        memset(a,0,sizeof(a));
                                            }
                void print()
                        {
                                    for (int i=len;i>=1;i--) printf("%d",a[i]);
                                            printf("\n");
                                                }
};
int n;
hugeint f[210];
hugeint operator +(hugeint a,hugeint b)
{
        hugeint c;
            c.len=max(a.len,b.len)+1;
                int x=0;
                    for (int i=1;i<=c.len;i++)
                            {
                                        c.a[i]=a.a[i]+b.a[i]+x;
                                                x=c.a[i]/10;
                                                        c.a[i]=c.a[i]%10;
                                                            }
                        while (c.len>1&&c.a[c.len]==0) c.len--;
                            return c;
}
int main()
{
    f[1].len=f[1].a[1]=1;
    f[2].len=1;f[2].a[1]=2;
    for (int i=3;i<=200;i++) f[i]=f[i-1]+f[i-2];
    while (scanf("%d",&n)!=EOF) f[n].print();
}