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 N;
string s;

int main(){

cin>>N>>s;

int x=0,Max=0;
for(int i=0; i<s.size(); i++){
    if(s[i]=='I') x++;
    if(s[i]=='D') x--;
    Max=max(Max,x);
}

cout<<Max<<endl;

}