t = int(input())
count = 0
count = t//5
if t%5==0:
print(count)
else:
print(count+1)838D - Airplane Arrangements | 148B - Escape |
847G - University Classes | 1110A - Parity |
1215B - The Number of Products | 604C - Alternative Thinking |
1204C - Anna Svyatoslav and Maps | 322A - Ciel and Dancing |
1689B - Mystic Permutation | 1711B - Party |
1702D - Not a Cheap String | 1714F - Build a Tree and That Is It |
1703F - Yet Another Problem About Pairs Satisfying an Inequality | 610A - Pasha and Stick |
1200A - Hotelier | 1091A - New Year and the Christmas Ornament |
1352B - Same Parity Summands | 1102A - Integer Sequence Dividing |
630B - Moore's Law | 1004A - Sonya and Hotels |
1680B - Robots | 1690A - Print a Pedestal (Codeforces logo) |
1295A - Display The Number | 1077A - Frog Jumping |
1714G - Path Prefixes | 1369C - RationalLee |
289B - Polo the Penguin and Matrix | 1716A - 2-3 Moves |
1670B - Dorms War | 1716B - Permutation Chain |