#include <stdio.h>

int main(void) {
    int fib;
    printf("fib? fib! fib? ");
    scanf("%d", &fib);

    int current = 0;
    int next = 1;

    if (fib < 1) {
        printf("Wait, wat?\n");
        return 1;
    }

    if (fib == 1) {
        printf("fib: %d\n", current);
        return 0;
    }

    for (int i = 2; i < fib; ++i) {
        int new = current + next;
        current = next;
        next = new;
    }

    printf("fib: %d\n", next);

    return 0;
}