You have an integer variable x. Initially, x=0.

Some person gave you a string S of length N, and using the string you performed the following operation N times. In the i-th operation, you incremented the value of x by 1 if S_i=`I`, and decremented the value of x by 1 if S_i=`D`.

Find the maximum value taken by x during the operations (including before the first operation, and after the last operation).

Constraints

* 1≤N≤100
* |S|=N
* No characters except `I` and `D` occur in S.

Input

The input is given from Standard Input in the following format:


N
S


Output

Print the maximum value taken by x during the operations.

Examples

Input

5
IIDID


Output

2


Input

7
DDIDDII


Output

0
import java.util.*;
public class Main{
 public static void main(String[] args){
   Scanner sc = new Scanner(System.in);
 
   int N = sc.nextInt();
   char[] c = sc.next().toCharArray();
   
   int tmp = 0;
   int ans = 0;
   for(int i=0;i<N;i++)
   {
     if(c[i]=='I')
     {
       tmp++;
     }  
     else
     {
       tmp--;
     }
     if(tmp>ans) ans=tmp;
   } 
   System.out.println(ans);
 }
}