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

void collatz_len_and_peek(uint64_t x, uint64_t *steps, uint64_t *peek);

int main() {
    uint64_t steps, peak;
    collatz_len_and_peek(13, &steps, &peak);
    printf("steps=%lu, peak=%lu\n", steps, peak);
    return 0;
}