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
#include<bits/stdc++.h>
using namespace std;
int main(){
	int x,count=0,MAX=0;
	cin>>x;
	char s[x];
	for(int i=0;i<x;i++){
	cin>>s[i];
	if(s[i]=='I')
	count++;
	else
	count--;
	if(count>MAX)
	MAX=count;
	}
	
cout<<MAX;	
}