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.io.*;

public class Main{

    public static void main(String[] args) throws IOException{
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	String N_moji = br.readLine();
	int N = Integer.parseInt(N_moji);
	String S = br.readLine();
	int x_max = 0,i,x = 0;
	for(i = 0; i < N; i++){
	    if(S.charAt(i) == 'D'){
		x--;
	    }
	    else{
		x++;
		if(x_max <= x){
		    x_max = x;
		}
	    }
	}
	System.out.println(x_max);
    }
}
		
	    
	    
	    
	
