#include <stdio.h>
int main() {
    int n;
    int fib[20] = { 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765};
    scanf("%d", &n);
    printf("%d\n", fib[n-1]);
     return 0;
}