CodeForces 977 B.Two-gram【字符串】

B. Two-gram

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

Two-gram is an ordered pair (i.e. string of length two) of capital Latin letters. For example, "AZ", "AA", "ZA" — three distinct two-grams.

You are given a string $s$ consisting of $n$ capital Latin letters. Your task is to find any two-gram contained in the given string as a substring (i.e. two consecutive characters of the string) maximal number of times. For example, for string $s$ = "BBAABBBA" the answer is two-gram "BB", which contained in $s$ three times. In other words, find any most frequent two-gram.

Note that occurrences of the two-gram can overlap with each other.

Input

The first line of the input contains integer number $n$ ($2\le n\le 100$) — the length of string $s$. The second line of the input contains the string $s$ consisting of $n$ capital Latin letters.

Output

Print the only line containing exactly two capital Latin letters — any two-gram contained in the given string $s$ as a substring (i.e. two consecutive characters of the string) maximal number of times.

Examples

input

Copy

7
ABACABA

output

Copy

AB

input

Copy

5
ZZZAA

output

Copy

ZZ

Note

In the first example "BA" is also valid answer.

题意：求出现次数最多的two-gram的子串，一个two-gram串是指在原字符串中出现的连续的两个字母。

            做题的时候zzzaa思考了好久为什么输出是zz，中间那个z用了两次，所以输出zz。

AC代码：

#include<stdio.h>
#include<string.h>
int count[30][30];
int main(void)
{  
    int n;  
    char s[110]; 
    scanf("%d",&n);
	scanf("%s",s); 
    for(int i=0; i < n-1;i++)
	{  
        int a = s[i]-'A';  
        int b = s[i+1]-'A';  
        count[a][b]++;  
    }  
    int max=0;
	int first=0;
	int second=0;  
    for(int i = 0;i < 26; i++)  
    	for(int j = 0;j < 26; j++)
		{  
        	if(max < count[i][j])
			{  
            first = i;  
            second = j;  
            max = count[i][j];  
       		}  
    }  
    printf("%c%c\n",first+'A',second+'A');  
    return 0;  
}