// AOJ 1568: String Conversion
// 2017.10.23 bal4u@uu

#include <stdio.h>
#include <stdlib.h>

#define ABS(a)  ((a)>=0?(a):-(a))

int a['z'+1], b['z'+1];
char buf[100005], *p;

int cmp(int *a, int *b) { return *b - *a; }
int main() 
{
	int i, ans;

	fgets(buf, 100001, stdin);
	fgets(p=buf, 100001, stdin);
	while (*p > 0x20) a[*p++]++;
	fgets(p=buf, 100001, stdin);
	while (*p > 0x20) b[*p++]++;
	qsort(a+'a', 26, sizeof(int), cmp);
	qsort(b+'a', 26, sizeof(int), cmp);
	for (ans = 0, i = 'a'; i <= 'z'; i++) {
		if (a[i] > 1) ans += ABS(a[i] - b[i]);
	}
	printf("%d\n", ans);
	return 0; 
}