#include <stdio.h>
#include "stdint.h"

uint64_t fibonacci(uint64_t n);

int main() {
	uint64_t n;
	int ret;
	do {
		ret=scanf(" %lu", &n);
		if (ret==EOF) break;
		if (ret==0) getchar();	// discard invalid input
		if (ret<1) continue;	// discard incomplete input
		printf("%lu\n", fibonacci(n));
	} while(1);
	return 0;
}