#include #include using namespace std; // (1+sqrt(3)) ^ n + (1 - sqrt(3)) ^ nは次のような数列になる // 2, 2, 8, 20, 56, 152, ... f(n+2)=2(f(n + 1) + f(n)) // -1 < (1 - sqrt(3)) ^ n < 1より上の数列の値-1か+0が求める整数 // const int64_t MOD = 1000; void next(vector &x, const vector &first, long MOD) { long last = x.back(); for(int i = x.size() - 2; i >= 0 ; i--) x[i + 1] = x[i]; x[0] = 0; for(int i = 0; i < x.size(); i++) x[i] = (MOD + x[i] - (long)last * first[i] % MOD) % MOD; } vector next2N(const vector &x, const vector &first, long MOD) { vector tmp(x); vector result(x.size()); for(int i = 0; i < x.size(); i++) { for(int j = 0; j < tmp.size(); j++) { result[j] = (result[j] + MOD - x[i] * tmp[j]) % MOD; } next(tmp, first, MOD); } return result; } long calc(const vector &poly, const vector &x, long MOD, int ofs = 0) { __int128_t ret = 0; for(int i = 0; i < poly.size(); i++) { ret += x[i + ofs] * poly[i] % MOD; ret %= MOD; } return (MOD - ret) % MOD; } long kitamasa(const vector &poly, const vector &x, int64_t N, long MOD) { if(N < poly.size()) return x[N]; int t = poly.size(), l = 0; while(t > 0) t >>= 1, l++; for(int i = 0; i <= l; i++) { if(N >> (63 - __builtin_clzl(N) - l + i) & 1) { t |= 1LL << i; } } long cur = poly.size(); vector curPoly = poly; vector poy2 = poly; while(cur < t) { if(cur == N) { return calc(curPoly, x, MOD); } next(curPoly, poly, MOD); cur++; } vector ret(curPoly.size()); cur = 0; for(int i = 63 - __builtin_clzl(N) - l - 1; i >= 0; i--) { curPoly = next2N(curPoly, poly, MOD); if(N >> i & 1) next(curPoly, poly, MOD); } return calc(curPoly, x, MOD); } int main() { int n; cin >> n; vector poly(2, -2); vector iv(2, 2); cout << (kitamasa(poly, iv, n, MOD) + (n % 2 == 0 ? MOD - 1 : 0)) % MOD<< endl; }