[ Source Code ]

#include <stdio.h>

#include <string.h>

int main ( void ) {
        int                check[26], check2[26], loop, input1_len;
	int                input2_len;

        char               input1[1001], input2[1001];



  



  




        while ( gets ( input1 ) ) {
                gets ( input2 );
                input1_len = strlen ( input1 );

                input2_len = strlen ( input2 );
                // 변수 초기화

                memset ( check, 0, sizeof ( check ) );

                memset ( check2, 0, sizeof ( check2 ) );
                // 첫번째 인풋에서 있는 문자열 체크

                for ( loop = 0 ; loop < input1_len ; loop++ ) {

                        check[input1[loop]-‘a’] += 1;

                }
                // 두번째 인풋에서 있는 문자열 체크

                for ( loop = 0 ; loop < input2_len ; loop++ ) {

                        check2[input2[loop]-‘a’] += 1;

                }
                for ( loop = 0 ; loop < 26 ; loop++ ) {

                        while ( check[loop] && check2[loop] ) {

                                printf ( “%c“, (char) loop + ‘a’ );

                                check[loop]–;

                                check2[loop]–;

                        }

                }

                printf ( “\n“ );

                memset ( input1, 0, sizeof ( input1 ) );

                memset ( input2, 0, sizeof ( input2 ) );
        }
        return 0;
}