#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>
/* The state word must be initialized to non-zero */
uint32_t xorshift32(uint32_t curr)
{
    /* Algorithm "xor" from p. 4 of Marsaglia, "Xorshift RNGs" */
    uint32_t x = curr;
    x ^= x << 13;
    x ^= x >> 17;
    x ^= x << 5;
    return x;
}

int main() {
    std::cerr << "started" << std::endl;
    const uint32_t mod = 1u << 31;
    std::vector<bool> was(mod);
    std::cerr << "memory allocated" << std::endl;
    uint32_t x = 1, k = 0;
    while(!was[x]) {
        k++;
        if (k % (1 << 20) == 0) { std::cerr << "current k = " << k << std::endl; }
        was[x] = true;
        x = xorshift32(x) % mod;
    }
    std::cout << "ended with k = " << k << std::endl;
    return 0;
}