Adding tower of hanoi problem's program

tower_of_hanoi.py

@@ -0,0 +1,41 @@
+'''Tower of Hanoi is a mathematical puzzle where we have three rods and n disks. The objective of the puzzle is to move
+    the entire stack to another rod, obeying the following simple rules:
+1) Only one disk can be moved at a time.
+2) Each move consists of taking the upper disk from one of the stacks and placing it on top of another stack i.e. a disk
+    can only be moved if it is the uppermost disk on a stack.
+3) No disk may be placed on top of a smaller disk.
+APPROACH:
+Take an example for 2 disks :
+Let rod 1 = 'SOURCE', rod 2 = 'TEMPORARY', rod 3 = 'DESTINATION'.
+
+Step 1 : Shift first disk from 'SOURCE' to 'TEMPORARY'.
+Step 2 : Shift second disk from 'SOURCE' to 'DESTINATION'.
+Step 3 : Shift first disk from 'TEMPORARY' to 'DESTINATION'.
+
+The pattern here is :
+Shift 'n-1' disks from 'SOURCE' to 'TEMPORARY'.
+Shift last disk from 'SOURCE' to 'DESTINATION'.
+Shift 'n-1' disks from 'TEMPORARY' to 'DESTINATION'.
+'''
+def toh(n,s,t,d):
+    if n==1:
+        print(s,'-->',d)
+        return
+    toh(n-1,s,d,t)
+    print(s,'-->',d)
+    toh(n-1,t,s,d)
+
+if __name__=="__main__":
+    while 1:
+
+        n = int(input('''Enter number of disks:'''))
+
+        if n<0:
+            print("Try Again with a valid input")
+            continue
+        elif n==0:
+            break
+        toh(n,'Source','Temporary','Destination')
+
+        print('ENTER 0 TO EXIT')
+