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 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <stdbool.h>
#include <string.h>



/*以下便利なマクロを定義する。*/

#define rep(i, min, max) for(i=min; i<=max; i=i+1)



#define if_forall(i, min, max, prop)\
\
	rep(i, min, max)\
	{\
		if(!(prop))\
		{\
			break;\
		}\
	}\
\
	if(i==max+1)\



#define if_exists(i, min, max, prop)\
\
	rep(i, min, max)\
	{\
		if(prop)\
		{\
			break;\
		}\
	}\
\
	if(i<max+1)\



#define sum(i, min, max, sequence, answer)\
{\
	answer=0;\
	rep(i, min, max)\
	{\
		answer=answer+sequence;\
	}\
}\



#define prod(i, min, max, sequence, answer)\
{\
	answer=1;\
	rep(i, min, max)\
	{\
		answer=answer*sequence;\
	}\
}\











/*以下便利な関数を定義する。*/

void fill_int(int array[], int min, int max, int element)
{
	int i=min;

	rep(i, min, max)
	{
		array[i]=element;
	}

}



void fill_int_array(int size_1, int size_2, int array[size_1][size_2], int i_min, int i_max, int j_min, int j_max, int element)
{
	int i=i_min;

	rep(i, i_min, i_max)
	{
		fill_int(array[i], j_min, j_max, element);
	}
}



void fill_char(char array[], int min, int max, char element)
{
	int i=min;

	rep(i, min, max)
	{
		array[i]=element;
	}

}



void fill_char_array(int size_1, int size_2, char array[size_1][size_2], int min, int max, char element[])
{
	int i=min, j=0;

	rep(i, min, max)
	{
		fill_char(array[i], 0, size_2-2, '\0');
		for(j=0; j<strlen(element); j=j+1)
		{
			array[i][j]=element[j];
		}
	}
}



void  swap_int(int* x, int* y)
{
    int  tmp;

    tmp = *x;
    *x = *y;
    *y = tmp;
}



void  swap_int_array(int x[], int y[], int min, int max)
{
	int i;

    rep(i, min, max)
	{
		swap_int(&x[i], &y[i]);
	}
}



void  swap_char(char* x, char* y)
{
    char  tmp;

    tmp = *x;
    *x = *y;
    *y = tmp;
}



void  swap_char_array(char x[], char y[], int min, int max)
{
	int i;

    rep(i, min, max)
	{
		swap_char(&x[i], &y[i]);
	}
}



void reverse_char(char array[], int min, int max)
{
	int i;

	rep(i, min, (min+max)/2)
	{
		swap_char(&array[i], &array[min+max-i]);
	}
}



int max_int(int var1, int var2)
{
	int answer=var1;

	if(answer<var2)
	{
		answer=var2;
	}

	return answer;
}



int min_int(int var1, int var2)
{
	int answer=var1;

	if(answer>var2)
	{
		answer=var2;
	}

	return answer;
}



double max_double(double var1, double var2)
{
	double answer=var1;

	if(answer<var2)
	{
		answer=var2;
	}

	return answer;
}



double min_double(double var1, double var2)
{
	double answer=var1;

	if(answer>var2)
	{
		answer=var2;
	}

	return answer;
}



long int pow_int(int base, unsigned int exponent)
{
	long int answer=1;

	answer=(long int)pow((double)base, (double)exponent);

	return answer;
}



long int pow_int_mod(int base, unsigned int exponent, int mod)
{
	long int answer=1;
	while (exponent>0)
	{
		if (exponent&1)
		{
			answer=(answer*(base%mod))%mod;
			if(answer==0)
			{
				break;
			}
		}
		base=(base*base)%mod;
		exponent=exponent>>1;
	}
	return answer;
}



unsigned long int factorial(unsigned int num)
{
	unsigned int i=0;
	unsigned long int answer=1;
	rep(i, 2, num)
	{
		answer=answer*i;
	}
	return answer;
}



unsigned long int factorial_mod(unsigned int num, int mod)
{
	unsigned int i=0;
	unsigned long int answer=1;
	rep(i, 2, num)
	{
		answer=(answer*(i%mod))%mod;
		if(answer==0)
		{
			break;
		}
	}
	return answer;
}



unsigned long int combination(unsigned int n, unsigned int k)
{
	unsigned int i=0;
	unsigned long int numerator=1;
	unsigned long int denominator=1;

	k=min_int(k, n-k);

	rep(i, 2, k)
	{
		numerator=numerator*(n+1-i);
		denominator=denominator*i;
	}
	return numerator/denominator;
}



double combination_general(double alpha, unsigned int k)
{
	unsigned int i;
	double numerator=1;
	unsigned long int denominator=1;

	rep(i, 1, k)
	{
		numerator=numerator*(alpha+1-i);
		denominator=denominator*i;
	}
	return numerator/denominator;
}



int gcd(int a, int b)
{
	if(a<b)
	{
		swap_int(&a, &b);
	}

	int r=a%b;

	while(r!=0)
	{
		a=b;
		b=r;
		r=a%b;
	}

	return b;
}



int lcm(int a, int b)
{
	return (a/gcd(a, b))*b;
}



int order(long int num)
{
	int answer=-1;
	while(num!=0)
	{
		num=num/10;
		answer=answer+1;
	}
	return answer;
}



long int convert_adic_int(char num[], unsigned int p_adic, unsigned int q_adic)
{
	int i=0;
	long int answer=0;
	bool sgn=0;
	long int tmp=strtol(num, NULL, p_adic);

	if(tmp<0)
	{
		sgn=1;
		tmp=-tmp;
	}

	while(tmp>0)
	{
		answer=answer+(tmp%q_adic)*pow_int(10, i);
		tmp=tmp/q_adic;
		i=i+1;
	}

	if(sgn==0)
	{
		return answer;
	}
	else
	{
		return -answer;
	}
}



void convert_adic_char(char num[], unsigned int p_adic, unsigned int q_adic)
{
	int i=0;
	int mod[32]={0};
	bool sgn=0;
	int digit=0;
	long int tmp=strtol(num, NULL, p_adic);

	if(tmp<0)
	{
		sgn=1;
		tmp=-tmp;
	}

	while(tmp>0)
	{
		mod[i]=tmp%q_adic;

		digit=i;
		tmp=tmp/q_adic;
		i=i+1;
	}

	fill_char(num, 0, min_int(0, strlen(num)-1), '\0');

	if(sgn==1)
	{
		num[0]='-';
	}

	rep(i, 0, digit)
	{
		if(mod[i]<10)
		{
			num[sgn+digit-i]='0'+mod[i];
		}
		else if(mod[i]<q_adic)
		{
			num[sgn+digit-i]='a'+(mod[i]-10);
		}
	}
}



int sum_digit(int num)
{
	int answer=0;
	num=abs(num);

	while(num>0)
	{
		answer=answer+num%10;
		num=num/10;
	}
	return answer;
}



int count_mod(int min, int max, int num)
{
	if(min>0)
	{
		return max/num-(min-1)/num;
	}
	else if(min==0)
	{
		return max/num+1;
	}
	else
	{
		return -1;
	}
}



void shift_char(char array[], int min, int max, int num)
{
	int i;

	for(i=max; i>=min; i=i-1)
	{
		array[i+num]=array[i];
	}

	rep(i, min, min+num-1)
	{
		array[i]='\0';
	}
}



void convert_char(char array[], int min, int max, char pre, char post)
{
	int i=min;

	rep(i, min, max)
	{
		if(array[i]==pre)
		{
			array[i]=post;
		}
	}
}



void sort_asc_int(int array[], int min, int max)
{
	int i, j;

	rep(i, min, max)
	{
		rep(j, i+1, max)
		{
			if(array[i]>array[j])
			{
				swap_int(&array[i], &array[j]);
			}
		}
	}
}



void sort_des_int(int array[], int min, int max)
{
	int i, j;

	rep(i, min, max)
	{
		rep(j, i+1, max)
		{
			if(array[i]<array[j])
			{
				swap_int(&array[i], &array[j]);
			}
		}
	}
}



void sort_asc_char_dic(char array[], int min, int max)
{
	int i, j;

	rep(i, min, max)
	{
		rep(j, i+1, max)
		{
			if(strcmp(&array[i], &array[j])>0)
			{
				swap_char(&array[i], &array[j]);
			}
		}
	}
}



void sort_asc_char_array_dic(int size_1, int size_2, char array[size_1][size_2], int min, int max)
{
	int i, j;

	rep(i, min, max)
	{
		rep(j, i+1, max)
		{
			if(strcmp(array[i], array[j])>0)
			{
				swap_char_array(array[i], array[j], 0, size_2-1);
			}
		}
	}
}



void sort_des_char_dic(char array[], int min, int max)
{
	int i, j;

	rep(i, min, max)
	{
		rep(j, i+1, max)
		{
			if(strcmp(&array[i], &array[j])<0)
			{
				swap_char(&array[i], &array[j]);
			}
		}
	}
}



void sort_des_char_array_dic(int size_1, int size_2, char array[size_1][size_2], int min, int max)
{
	int i, j;

	rep(i, min, max)
	{
		rep(j, i+1, max)
		{
			if(strcmp(array[i], array[j])<0)
			{
				swap_char_array(array[i], array[j], 0, size_2-1);
			}
		}
	}
}



int max_int_array(int array[], int min, int max)
{
	int i;
	int answer;

	answer=array[min];

	for(i=min+1; i<=max; i=i+1)
	{
		answer=max_int(answer, array[i]);
	}

	return answer;
}



void max_int_array_num(int array[], int min, int max, int answer[])
{
	int i=min;
	int count=0;
	int max_value=max_int_array(array, min, max);

	fill_int(answer, 0, max-min, -1);

	rep(i, min, max)
	{
		if(array[i]==max_value)
		{
			answer[count]=i;
			count=count+1;
		}
	}
}



int min_int_array(int array[], int min, int max)
{
	int i;
	int answer;

	answer=array[min];

	for(i=min+1; i<=max; i=i+1)
	{
		answer=min_int(answer, array[i]);
	}

	return answer;
}



void min_int_array_num(int array[], int min, int max, int answer[])
{
	int i=min;
	int count=0;
	int min_value=min_int_array(array, min, max);

	fill_int(answer, 0, max-min, -1);

	rep(i, min, max)
	{
		if(array[i]==min_value)
		{
			answer[count]=i;
			count=count+1;
		}
	}
}



double max_double_array(double array[], int min, int max)
{
	int i=min;
	double answer;

	answer=array[min];

	rep(i, min+1, max)
	{
		answer=max_double(answer, array[i]);
	}

	return answer;
}



void max_double_array_num(double array[], int min, int max, int answer[])
{
	int i=min;
	int count=0;
	double max_value=max_double_array(array, min, max);

	fill_int(answer, 0, max-min, -1);

	rep(i, min, max)
	{
		if(array[i]==max_value)
		{
			answer[count]=i;
			count=count+1;
		}
	}
}



double min_double_array(double array[], int min, int max)
{
	int i=min;
	double answer;

	answer=array[min];

	rep(i, min+1, max)
	{
		answer=min_double(answer, array[i]);
	}

	return answer;
}



void min_double_array_num(double array[], int min, int max, int answer[])
{
	int i=min;
	int count=0;
	double min_value=min_double_array(array, min, max);

	fill_int(answer, 0, max-min, -1);

	rep(i, min, max)
	{
		if(array[i]==min_value)
		{
			answer[count]=i;
			count=count+1;
		}
	}
}




int max_char_array_dic(int size_1, int size_2, char array[size_1][size_2], int min, int max)
{
	int i;
	int answer=min;

	rep(i, min+1, max)
	{
		if(strcmp(array[answer], array[i])<0)
		{
			answer=i;
		}
	}

	return answer;
}



int min_char_array_dic(int size_1, int size_2, char array[size_1][size_2], int min, int max)
{
	int i;
	int answer=min;

	rep(i, min+1, max)
	{
		if(strcmp(array[answer], array[i])>0)
		{
			answer=i;
		}
	}

	return answer;
}



int sum_array(int array[], int min, int max)
{
	int i=min;
	int answer=0;

	rep(i, min, max)
	{
		answer=answer+array[i];
	}

	return answer;
}



bool detect_int(int array[], int min, int max, int element)
{
	int i;
	bool answer=0;

	if_exists(i, min, max, array[i]==element)
	{
		answer=1;
	}

	return answer;
}



bool detect_char(char array[], int min, int max, char element)
{
	int i;
	bool answer=0;

	if_exists(i, min, max, array[i]==element)
	{
		answer=1;
	}
	return answer;
}



bool detect_char_array(char array[], int min, int max, char element[], int start, int goal)
{
	int i, j;
	bool answer=0;

	if(goal-start<=max-min)
	{
		rep(i, min, max-(goal-start))
		{
			if_forall(j, start, goal, array[i+j-start]==element[j])
			{
				answer=1;
				break;
			}
		}
	}

	return answer;
}




int count_differentelement_int(int array[], int min, int max)
{
	int i=min;
	int pickup[max];
	fill_int(pickup, 0, max, 0);
	int answer=0;

	rep(i, min, max)
	{
		if(detect_int(pickup, 0, answer-1, array[i])==0)
		{
			pickup[answer]=array[i];
			answer=answer+1;
		}
	}

	return answer;
}



int count_differentelement_char(char array[], int min, int max)
{
	int i=min;
	char pickup[max];
	fill_char(pickup, 0, max, '\0');
	int answer=0;

	rep(i, min, max)
	{
		if(detect_char_array(pickup, 0, answer-1, array, i, i)==0)
		{
			pickup[answer]=array[i];
			answer=answer+1;
		}
	}

	return answer;
}



int count_equalelement_int(int array[], int min, int max, int element)
{
	int i;
	int answer=0;

	rep(i, min, max)
	{
		if(array[i]==element)
		{
			answer=answer+1;
		}
	}

	return answer;
}



int count_equalelement_char(char array[], int min, int max, char element)
{
	int i;
	int answer=0;

	rep(i, min, max)
	{
		if(array[i]==element)
		{
			answer=answer+1;
		}
	}

	return answer;
}



int count_equalelement_char_array(int size_1, int size_2, char array[size_1][size_2], int min, int max, char element[])
{
	int i;
	int answer=0;

	rep(i, min, max)
	{
		if(strcmp(array[i], element)==0)
		{
			answer=answer+1;
		}
	}
	return answer;
}



void scanf_int_array(int array[], int min, int max)
{
	int i;
	rep(i, min, max)
	{
		scanf("%d", &array[i]);
	}
}



void scanf_int_array_2(int array1[], int array2[], int min, int max)
{
	int i;
	rep(i, min, max)
	{
		scanf("%d %d", &array1[i], &array2[i]);
	}
}



void scanf_int_array_3(int array1[], int array2[], int array3[], int min, int max)
{
	int i;
	rep(i, min, max)
	{
		scanf("%d %d %d", &array1[i], &array2[i], &array3[i]);
	}
}



void scanf_char(char array[], int num)
{
	scanf("%s", array);
	shift_char(array, 0, strlen(array)-1, num);
}



void scanf_char_array(int size_1, int size_2, char array[size_1][size_2], int min, int max, int num)
{
	int i;
	rep(i, min, max)
	{
		scanf_char(array[i], num);
	}

}



void printf_int_array(int array[], int min, int max)
{
	int i;
	rep(i, min, max)
	{
		printf("%d\n", array[i]);
	}
}



void printf_char_array(char array[], int min, int max)
{
	int i;
	for(i=min; i<=max; i=i+1)
	{
		printf("%c", array[i]);
	}
}












int main()
{
	int i, j;

	char S[11]="\0";
	scanf("%s", S);

	int regi[10]={0};

	rep(i, 0, 9)
	{
		if(S[i]=='A' || S[i]=='C' || S[i]=='G' || S[i]=='T')
		{
			rep(j, i+1, 10)
			{
				if(!(S[j]=='A' || S[j]=='C' || S[j]=='G' || S[j]=='T'))
				{
					regi[i]=j-i;
					break;
				}
			}
		}
		else
		{
			regi[i]=0;
		}
	}
	printf("%d\n", max_int_array(regi, 0, 9));
	return 0;
}