#include <cstdio>
#include <cstring>

using namespace std;

FILE *fin = fopen("nunta.in", "r");
FILE *fout = fopen("nunta.out", "w");

int n, i, t;
int A[200], B[200], C[200];

void Sum(){
    int i;
    t = 0;
    for(i = 1; i <= A[0] || i <= B[0] || t; i++){
        t += A[i] + B[i];
        C[i] = t % 10;
        t /= 10;
    }
    C[0] = i - 1;
}

void MaxPoint(){
    fscanf(fin, "%d", &n);
    if(n == 1){
        fprintf(fout, "1");
    } else {
        A[0] = B[0] = A[1] = B[1] = 1;
        for(i = 1; i < n; i++){
            Sum();
            memcpy(A, B, sizeof(B));
            memcpy(B, C, sizeof(C));
        }
        for(i = C[0]; i > 0; i--){
            fprintf(fout, "%d", C[i]);
        }
    }
}

int main(){
    MaxPoint();
    return 0;
}