import java.math.*;
class Fibonacci {
private Fibonacci() {}
public static BigInteger calc(int n) {
BigInteger[] dp = new BigInteger[n+1];
dp[0] = dp[1] = BigInteger.ONE;
for(int i=2; i<n; i++) {
dp[i] = dp[i-2].add(dp[i-1]);
}
return dp[n-1];
}
}
public class Main {
private void doIt(int n) {
System.out.printf("%d: %s\n", n, Fibonacci.calc(n));
}
public static void main(String[] args) {
new Main().doIt(Integer.parseInt(args[0]));
}
}