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)

/*ex5-4
ryo_1129*/

#include <stdio.h>

int main(void){
    //入力の文字列は10文字以下なので\0を含めて11で定義する
    char str[11],*ptr;
    //ACGT配列の長さと、最長の長さをいれる変数
    int length_counter=0,max_length=0;
    scanf("%s",str);
    ptr = str;
    while(*ptr){
        //ACTGが続く間はlength_counterに部分文字列の長さを記録する
        if(*ptr=='A' || *ptr=='G' || *ptr=='C' || *ptr=='T'){
            length_counter++;
        //ACGT以外の文字が出てきたら、部分文字列が最長か比較しlength_counterをリセットする
        }else{
            if(max_length<length_counter){
                max_length = length_counter;
            }
            length_counter=0;
        }
        ptr++;
    }
    //AGCTのみで文字列が構成されていた場合
    if(max_length<length_counter){
        max_length = length_counter;
    }

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