Problem:
Score : 200 points

Problem Statement

You are given a string S consisting of uppercase English letters. Find the length of the longest ACGT string that is a substring (see Notes) of S.

Here, a ACGT string is a string that contains no characters other than A, C, G and T.

Notes

A substring of a string T is a string obtained by removing zero or more characters from the beginning and the end of T.

For example, the substrings of ATCODER include TCO, AT, CODER, ATCODER and (the empty string), but not AC.

Constraints

S is a string of length between 1 and 10 (inclusive).

Each character in S is an uppercase English letter.

Input

Input is given from Standard Input in the following format:

S

Output

Print the length of the longest ACGT string that is a substring of S.

Sample Input 1

ATCODER

Sample Output 1

3

Among the ACGT strings that are substrings of ATCODER, the longest one is ATC.

Sample Input 2

HATAGAYA

Sample Output 2

5

Among the ACGT strings that are substrings of HATAGAYA, the longest one is ATAGA.

Sample Input 3

SHINJUKU

Sample Output 3

0

Among the ACGT strings that are substrings of SHINJUKU, the longest one is (the empty string).

Solution in C (GCC 9.2.1) (judge verdict: Accepted)

/* ex 5_4
   Tarara */

#include <stdio.h>

// 文字列長は10よりも大きくする
#define MAX_LEN 15

// a, bの内大きい値を返す
int max(int a, int b)
{
    return a > b ? a : b;
}

int main(void)
{
    //ptr: strの各要素へのポインタ
    char str[MAX_LEN], *ptr;
    int max_len, tmp_len;
    
    max_len = 0;
    tmp_len = 0;

    // 入力
    scanf("%s", str);

    // 文字列先頭から1文字づつ見る
    ptr = str;
    while (*ptr)
    {
        if (*ptr == 'A' || *ptr == 'C' || *ptr == 'G' || *ptr == 'T')
            tmp_len++;

        // 文字列にACGT以外が現れたらACGT文字列でなくなるため，文字列長のカウントを中断する
        // 過去のACGT文字列とその長さを比較し，ACGT文字列の最大長を更新する
        else
        {
            max_len = max(max_len, tmp_len);
            tmp_len = 0;
        }
        ptr++;
    }
    // 最後の文字がACGT文字列に含まれる場合，ループの外でACGT文字列の最大長を更新する必要がある
    max_len = max(max_len, tmp_len);

    // 出力
    printf("%d\n", max_len);
    return 0;
}