I don't know about you but Niko loves NSU life so much. He always tries to show off that he is an NSUer. One day he found some wood letter cutouts lying on the plaza area. Niko was thinking about how many times he can produce “NSU” using those cutouts.
The first line contains an integer N (1 ≤ N ≤ 1000) which denotes the number of letters found by Niko. The second line contains a text of N characters. All those cutouts are upper case English alphabets.
Print the number of times “NSU” can be produced out of those cutouts.