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
   kanon */

#include <stdio.h>
#include <string.h>
#define SIZE 80

int main(void)
{
    //与えられる値を入れる数を宣言
    char str[SIZE], *ptr;
    int longest_len = 0, temp_len = 0;

    //変数に値を入力する
    scanf("%s", str);

    //文字列内で探索
    ptr = &str[0];

    while (*ptr != '\0')
    {
        //ATCGならtemp_lenを更新していく
        if (*ptr == 'A' || *ptr == 'T' || *ptr == 'C' || *ptr == 'G')
        {
            temp_len++;
        }
        /*ATCGでないなら更新をやめてtemp_len=0とする。
        このときもし、temp_lenの長さが今までの最長ATCG列longest_lenより
        長いならlongest_lenを更新する*/
        else
        {
            if (temp_len > longest_len)
                longest_len = temp_len;

            temp_len = 0;
        }
        //ポインタを次の文字にずらしていく
        ptr++;
    }

    if (temp_len > longest_len)
        longest_len = temp_len;

    //答えを出力
    printf("%d\n", longest_len);
    return 0;
}