#include int gcd(int u, int v); int main(){ int N; scanf("%d",&N); int x = (N*(N + 1)) / 2; printf("%d\n", gcd(x, x+N)); return 0; } int gcd(int u, int v) { int r; while (0 != v) { r = u % v; u = v; v = r; } return u; }