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 n;
	string s;
	cin >> n >> s;

	int x = 0;
	int mx = 0;

	for (int i=0; i < n; ++i) {
		x += (s[i]=='I') ? 1 : -1;
		mx = max(x, mx);
	}
	
	cout << mx << endl;
}