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
   seira3 */

#include <stdio.h>
#define SIZE 11 //10文字以下なので最大の要素数は\0を含めて11

int main(void){
    int ans = 0, count = 0;
    char str[SIZE], *ptr; //str: 文字列を格納する配列, ptr: strの各要素へのポインタ
    scanf("%s",&str[0]); //strに入力
    ptr = &str[0]; //ptrにstrのアドレスを代入
    while(*ptr){ //'\0'にだどり着くまでwhile文内の動作を行う
        if(*ptr=='A' || *ptr=='C' || *ptr=='G' || *ptr=='T'){ //もし*ptrが'A''C''G''T'のうちどれかならば
            count++; //countに1を足す
        }
        else{ //そうでなければcountを0でリセット
            count = 0;
        }
        if(ans < count){ //もしcountがansを上回ったら
            ans = count; //ansにcountを代入
        }
        ptr++; //隣にいくために一つずらす
    }
    printf("%d\n",ans); //答えであるansを出力
    return 0;
}