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).
N = int(input())
S = input()

ans = 0
highest = 0
for i in S:
    if i == "I":
        ans += 1
    else:
        ans -= 1
    print(ans)
    if highest <= ans:
        highest = ans 

print(highest)
N = int(input())
S = input()

ans = 0
highest = 0
for i in S:
    if i == "I":
        ans += 1
    else:
        ans -= 1
    if highest <= ans:
        highest = ans 

print(highest)