Problem:
Score : 200 points

Problem Statement

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.

Sample Input 1

5
IIDID

Sample Output 1

2

After each operation, the value of x becomes 1, 2, 1, 2 and 1, respectively. Thus, the output should be 2, the maximum value.

Sample Input 2

7
DDIDDII

Sample Output 2

0

The initial value x=0 is the maximum value taken by x, thus the output should be 0.

Solution in Go (1.6) (judge verdict: Accepted)

package main

import (
        "fmt"
)

func solution(n int, s string) int {
        out, x := 0, 0
        for i := 0; i < n; i++ {
                if s[i] == 'I' {
                        x++
                } else {
                        x--
                }
                out = max(out, x)
        }
        return out
}

func max(x, y int) int {
        if x > y {
                return x
        }
        return y
}
func main() {
        var n int
        var s string
        fmt.Scan(&n, &s)
        fmt.Println(solution(n, s))
}