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 "ATCoder"
    dada__      */
#include<stdio.h>
#include<string.h>
 
int main(void){
    char *ptr, *ptr2, sequence1[11], part_seq[11]="",longest_seq[11]="";
    scanf("%s", sequence1);//文字列の入力
    ptr=sequence1; //ptrに入力文字列の先頭アドレスを代入
    ptr2=part_seq; //ptr2に部分文字列の先頭アドレスを代入
 
    while(*ptr){
        while(*ptr){
            //文字列に'A','C','G','T'がでるまでptrを移動 
            if(*ptr!='A'&&*ptr!='C'&&*ptr!='G'&&*ptr!='T') ptr++;
            else break;
        }
 
        while(*ptr){
            //文字列が'A','C','G','T'の間は部分文字列としてコピー
            if(*ptr=='A'||*ptr=='C'||*ptr=='G'||*ptr=='T'){
                *ptr2++ = *ptr++;
            }else{//'A','C','G','T'以外で部分文字列終了
                *ptr2='\0';
                break;
            }
        }
        //最長部分文字列の更新
        if(strlen(part_seq)>strlen(longest_seq)) strcpy(longest_seq,part_seq);
        //ptr2を部分文字列の先頭に移動
        ptr2-=strlen(part_seq);
    }
    //最長の部分文字列の長さを出力
    printf("%d\n", strlen(longest_seq));
    return 0;
 
}