#include <cstdio>
#include <cstring>
#include <string>
#include <cmath>
#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <vector>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> PII;
#define fi first
#define se second
#define MP make_pair

int read() {
    int v = 0, f = 1;
    char c = getchar();
    while (c < 48 || 57 < c) {if (c == '-') f = -1; c = getchar();}
    while (48 <= c && c <= 57) v = (v << 3) + v + v + c - 48, c = getchar();
    return v * f;
}

struct hi {
    int l, a[210];
    hi() {
        l = 0;
        memset(a, 0, sizeof a);
    }
    void print() {
        for (int i = l; i >= 1; i--)
            printf("%d", a[i]);
        puts("");
    }
} f[210];
hi operator + (hi a, hi b) {
    hi c;
    c.l = max(a.l, b.l) + 1;
    int x = 0;
    for (int i = 1; i <= c.l; 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.l > 1 && c.a[c.l] == 0) c.l--;
    return c;
}
int n;
int main() {
    f[1].l = f[2].l = 1;
    f[1].a[1] = 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)) f[n].print();
}