#include int solve(int X) { if (X == 1) return 1; else if (X == 2) return 2; else if (X == 3) return 4; else if (X == 4) return 5; else if (X == 5) return 7; else { int ans = 13; while (X > 6) { ans += 6; X -= 1; } return ans; } } int main(){ int X; int trash = scanf("%d", &X); printf("%d\n", solve(X)); }