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
   yumizmiz */

#include <stdio.h>

//大きい方を返す関数
int max(int x,int y){
    if(x>y)
        return x;
    else
        return y;
}

int main(void){
    //10文字以下なので最大の要素数は\0を含めて11
    //ptr: sequenceの各要素へのポインタ
    char sequence[11], *ptr;

    scanf("%s", sequence);

    //ptrにsequenceの最初のポインタを渡す
    ptr = sequence;

    //最大のACGT文字列長
    int max_length = 0;
    //現在のACGT文字列長
    int length = 0;
    while(*ptr){

        //ACGTならカウントする，異なればリセット
        if(*ptr=='A'||*ptr=='C'||*ptr=='G'||*ptr=='T')
            ++length;
        else
            length = 0;
        
        //最大値を更新
        max_length = max(length, max_length);
        ++ptr;
    }

    printf("%d\n", max_length);
    return 0;
}